POWER ELECTRONICS.doc

8/14/2019 POWER ELECTRONICS.doc

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CHAPTER 10

POWER ELECTRONICS

INTRODUCTION TO POWER ELECTRONICS

Power Electronics is a field which combines Power (electric ower!" Electronics and

Control s#stems$ Power en%ineerin% deals with the static and rotatin% ower e&'iment for the

%eneration" transmission and distrib'tion of electric ower$ Electronics deals with the st'd# of

solid state semicond'ctor ower deices and circ'its for Power conersion to meet the desired

control ob)ecties (to control the o't't olta%e and o't't ower!$

Power electronics ma# be defined as the s'b)ect of alications of solid state ower

semicond'ctor deices (Th#ristors! for the control and conersion of electric ower$

Power electronics deals with the st'd# and desi%n of Th#ristorised ower controllers for

ariet# of alication li*e +eat control" Li%ht,Ill'mination control" -otor control . /C,DC

motor dries 'sed in ind'stries" +i%h olta%e ower s'lies" 0ehicle ro'lsion s#stems" +i%h

olta%e direct c'rrent (+0DC! transmission$

POWER ELECTRONIC /PPLIC/TIONS1

CO--ERCI/L /PPLIC/TIONS

+eatin% S#stems 0entilatin%" /ir Conditioners" Central Refri%eration" Li%htin%"

Com'ters and Office e&'iments" Uninterr'tible Power S'lies (UPS!" Eleators" and

Emer%enc# Lams$

DO-ESTIC /PPLIC/TIONS1Coo*in% E&'iments" Li%htin%" +eatin%" /ir Conditioners" Refri%erators 2 3ree4ers"

Personal Com'ters" Entertainment E&'iments" UPS$

INDUSTRI/L /PPLIC/TIONS1


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P'ms" comressors" blowers and fans$ -achine tools" arc f'rnaces" ind'ction f'rnaces"

li%htin% control circ'its" ind'strial lasers" ind'ction heatin%" weldin% e&'iments$

/EROSP/CE /PPLIC/TIONS1

Sace sh'ttle ower s'l# s#stems" satellite ower s#stems" aircraft ower s#stems$

TELECO--UNIC/TIONS1

5atter# char%ers" ower s'lies (DC and UPS!" mobile cell hone batter# char%ers$

TR/NSPORT/TION1

Traction control of electric ehicles" batter# char%ers for electric ehicles" electric

locomoties" street cars" trolle# b'ses" a'tomobile electronics incl'din% en%ine controls$

UTILIT6 S6STE-S1

+i%h olta%e DC transmission (+0DC!" static 0/R comensation (S0C!" /lternatie

ener%# so'rces (wind" hotooltaic!" f'el cells" ener%# stora%e s#stems" ind'ced draft fans and

boiler feed water 'ms$

78$7 DI33ERENCES 5ETWEEN ELECTRONICS /ND POWER

ELECTRONICS1

This &'estion can be answered in n'mber of wa#s$ The simlest wa# to sa# all the

electronics deices which deals with ower are coered in Power Electronics$ There are deices

which #o' do 'se in %eneral 'rose electronics li*e1 Diode" 59T" -3ETs etc$ 6o' will find

these deices in electronics 2 ower electronics both$ The deices 'sed in Power electronics

ma# differ in term of constr'ction 2 behaior from those 'sed in electronics$ There are t#e of

deices which #o' will find onl# IN PE" e:1 I;5T$

The onl# difference is that ower deices (e$%$ -OS3ETs! are made to handle m'ch

lar%er ower re&'irements$

Ordinar# deices are low c'rrent and low olta%e deices$


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Power deices are hi%h c'rrent and,or hi%h olta%e deices$

78$< POWER CON0ERTERS1

/ ower conerter is an electrical or electro=mechanical deice for conertin% electricalener%#$ It ma# be conertin% /C to or from DC" or the olta%e or fre&'enc#" or some

combination of these$

/mon%st the man# deices that are 'sed for this 'rose are>

Rectifier

Inerter

DC = DC conerter

/C = /C conerter

/C = DC CON0ERTER (RECTI3IER!1

/ rectifier is an electrical deice that conertsalternatin% c'rrent(/C!" which

eriodicall# reerses direction" to direct c'rrent(DC!" which is in onl# one direction" a rocess

*nown as rectification$

Rectifiers hae man# 'ses incl'din% as comonents ofower s'liesand as

detectorsof radiosi%nals$ Rectifiers ma# be made of solid statediodes" ac''m

t'bediodes" merc'r# arc ales"and other comonents$

DC = /C CON0ERTER (IN0ERTER!1

/n inerter is an electrical deice that conerts direct c'rrent (DC! to alternatin% c'rrent

(/C!> the conerted /C can be at an# re&'ired olta%e and fre&'enc# with the 'se of aroriate

transformers" switchin%" and control circ'its$

Solid=state inerters hae no moin% arts and are 'sed in a wide ran%e of alications"

from small switchin% ower s'lies in com'ters" to lar%e electric 'tilit# hi%h=olta%e direct
http://en.wikipedia.org/wiki/Alternating_currenthttp://en.wikipedia.org/wiki/Alternating_currenthttp://en.wikipedia.org/wiki/Direct_currenthttp://en.wikipedia.org/wiki/Direct_currenthttp://en.wikipedia.org/wiki/Power_supplyhttp://en.wikipedia.org/wiki/Power_supplyhttp://en.wikipedia.org/wiki/Detector_(radio)http://en.wikipedia.org/wiki/Detector_(radio)http://en.wikipedia.org/wiki/Radiohttp://en.wikipedia.org/wiki/Solid_state_(electronics)http://en.wikipedia.org/wiki/Diodehttp://en.wikipedia.org/wiki/Vacuum_tubehttp://en.wikipedia.org/wiki/Vacuum_tubehttp://en.wikipedia.org/wiki/Mercury_arc_valvehttp://en.wikipedia.org/wiki/Mercury_arc_valvehttp://en.wikipedia.org/wiki/Direct_currenthttp://en.wikipedia.org/wiki/Power_supplyhttp://en.wikipedia.org/wiki/Detector_(radio)http://en.wikipedia.org/wiki/Radiohttp://en.wikipedia.org/wiki/Solid_state_(electronics)http://en.wikipedia.org/wiki/Diodehttp://en.wikipedia.org/wiki/Vacuum_tubehttp://en.wikipedia.org/wiki/Vacuum_tubehttp://en.wikipedia.org/wiki/Mercury_arc_valvehttp://en.wikipedia.org/wiki/Alternating_current


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c'rrent alications that transort b'l* ower$ Inerters are commonl# 'sed to s'l# /C ower

from DC so'rces s'ch as solar anels or batteries$

DC = DC CON0ERTER (C+OPPERS!1

/ dc choer is a dc=to=dc olta%e conerter$ It is a static switchin% electrical aliance

that in one Electrical conersion" chan%es an in't fi:ed dc olta%e to an ad)'stable dc o't't

olta%e witho't Ind'ctie or caacitie intermediate ener%# stora%e$ The name choer is

connected with the fact that the o't't olta%e is a ?choed '@ &'asi=rectan%'lar ersion of the

in't dc olta%e$

/C = /C CON0ERTER1

/n /C,/C conerter conerts an/Cwaeforms'ch as the mains s'l#" to another /C

waeform" where the o't't olta%e and fre&'enc# can be set arbitraril#$

/C,/C conerters can be cate%ori4ed into

C#cloconerters

-atri: Conerters

78$A POWER ELECTRONIC SWITC+ES1

In electronics" a switch is an electrical comonent that can brea* an electrical circ'it"

interr'tin% the c'rrent or diertin% it from one cond'ctor to another$

/ ower electronic switch inte%rates a combination of ower electronic comonents or

ower semicond'ctors and a drier for the actiel# switchable ower semicond'ctors$ Theinternal f'nctional correlations and interactions of this inte%rated s#stem determine seeral

DIODES1

In electronics" a diode is a t#e of two=terminal electronic comonent with a nonlinear

c'rrent.olta%e characteristic$ / semicond'ctor diode" the most common t#e toda#" is a
http://en.wikipedia.org/wiki/Alternating_currenthttp://en.wikipedia.org/wiki/Alternating_currenthttp://en.wikipedia.org/wiki/Waveformhttp://en.wikipedia.org/wiki/Cycloconverterhttp://en.wikipedia.org/wiki/Alternating_currenthttp://en.wikipedia.org/wiki/Waveformhttp://en.wikipedia.org/wiki/Cycloconverter


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cr#stalline iece of semicond'ctor material connected to two electrical terminals$ / ac''m

t'be diode (now rarel# 'sed e:cet in some hi%h=ower technolo%ies! is a ac''m t'be with two

electrodes1 a late and a cathode$

The most common f'nction of a diode is to allow an electric c'rrent to ass in onedirection (called the diodeBs forward direction!" while bloc*in% c'rrent in the oosite direction

(the reerse direction!$ Th's" the diode can be tho'%ht of as an electronic ersion of a chec*

ale$ This 'nidirectional behaior is called rectification" and is 'sed to conert alternatin%

c'rrent to direct c'rrent" and to e:tract mod'lation from radio si%nals in radio receiers$

+oweer" diodes can hae more comlicated behaior than this simle on.off action$

Semicond'ctor diodes do not be%in cond'ctin% electricit# 'ntil a certain threshold olta%e is

resent in the forward direction (a state in which the diode is said to be forward biased!$ Theolta%e dro across a forward biased diode aries onl# a little with the c'rrent" and is a f'nction

of temerat're> this effect can be 'sed as a temerat're sensor or olta%e reference$

Semicond'ctor diodes hae nonlinear electrical characteristics" which can be tailored b#

ar#in% the constr'ction of their P.N )'nction$ These are e:loited in secial 'rose diodes that

erform man# different f'nctions$

Diodes were the first semicond'ctor electronic deices$ The discoer# of cr#stalsB

rectif#in% abilities was made b# ;erman h#sicist 3erdinand 5ra'n in 7$ The first

semicond'ctor diodes" called catBs whis*er diodes" deeloed aro'nd 7F8G" were made of

mineral cr#stals s'ch as %alena$ Toda# most diodes are made of silicon" b't other semicond'ctors

s'ch as %ermani'm are sometimes 'sed$

/ modern semicond'ctor diode is made of a cr#stal of semicond'ctor li*e silicon that hasim'rities added to it to create a re%ion on one side that contains ne%atie char%e carriers

(electrons!" called n=t#e semicond'ctor" and a re%ion on the other side that contains ositie

char%e carriers (holes!" called =t#e semicond'ctor$ The diodeBs terminals are attached to each

of these re%ions$ The bo'ndar# within the cr#stal between these two re%ions" called a PN


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)'nction" is where the action of the diode ta*es lace$ The cr#stal cond'cts a c'rrent of electrons

in a direction from the N=t#e side (called the cathode! to the P=t#e side (called the anode!" b't

not in the oosite direction$ +oweer" conentional c'rrent flows from anode to cathode in the

direction of the arrow (oosite to the electron flow" since electrons hae ne%atie char%e!$

/nother t#e of semicond'ctor diode" the Scott# diode" is formed from the contact

between a metal and a semicond'ctor rather than b# a .n )'nction$

T+6RISTORS

/ th#ristor is a solid=state semicond'ctor deice with fo'r la#ers of alternatin% n and =

t#e material$ The# act as bistable switches" cond'ctin% when their %ate receies a c'rrent 'lse"

and contin'e to cond'ct while the# are forward biased (that is" while the olta%e across the

deice is not reersed!$

Some so'rces define silicon controlled rectifiers and th#ristors as s#non#mo's$

Circ'it s#mbol for a th#ristor

3UNCTION

The th#ristor is a fo'r=la#er" three terminal semicond'ctin% deice" with each la#er

consistin% of alternatel# N=t#e or P=t#e material" for e:amle P=N=P=N$ The main terminals"

labeled anode and cathode" are across the f'll fo'r la#ers" and the control terminal" called the%ate" is attached to =t#e material near to the cathode$ (/ ariant called an SCSHSilicon

Controlled SwitchHbrin%s all fo'r la#ers o't to terminals$! The oeration of a th#ristor can be

'nderstood in terms of a air of ti%htl# co'led biolar )'nction transistors" arran%ed to ca'se the

self=latchin% action1


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Str'ct're on the h#sical and electronic leel" and the th#ristor s#mbol$

Th#ristors hae three states1

7$ Reerse bloc*in% mode H 0olta%e is alied in the direction that wo'ld be bloc*ed b# a

diode


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deices in arallel and can hae er# hi%h c'rrent handlin% caabilities in the order of h'ndreds

of amswith bloc*in% olta%es of G"888 0$

EJUI0/LENT CIRCUIT1

/n e:amination of reeals that if we moe erticall# ' from collector to emitter$ We

come across K" n= " la#er s$ Th's" I;5T can be tho'%ht of as the combination of -OS3ET

and K n= la#er s$ Th's" I;5T can be tho'%ht of as the combination of -OS3ET and K n=

transistor J7 $+ere Rd is resistance offered b# n.drift re%ion$ /ro:imate e&'ialent circ'it of

an I;5T$

-OS3ET
http://en.wikipedia.org/wiki/Ampshttp://en.wikipedia.org/wiki/Voltshttp://en.wikipedia.org/wiki/Voltshttp://en.wikipedia.org/wiki/Ampshttp://en.wikipedia.org/wiki/Volts


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The metal.o:ide.semicond'ctor field=effect transistor (-OS3ET" -OS=3ET" or -OS

3ET! is a transistor 'sed for amlif#in% or switchin% electronic si%nals$ The basic rincile of

this *ind of transistor was first roosed b# 9'li's Ed%ar Lilienfeld in 7F


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/ metal.o:ide.semicond'ctor field=effect transistor (-OS3ET! is based on the

mod'lation of char%e concentration b# a -OS caacitance between a bod# electrode and a %ate

electrode located aboe the bod# and ins'lated from all other deice re%ions b# a %ate dielectric

la#er which in the case of a -OS3ET is an o:ide" s'ch as silicon dio:ide$ If dielectrics other

than an o:ide s'ch as silicon dio:ide (often referred to as o:ide! are emlo#ed the deice ma# be

referred to as a metal.ins'lator.semicond'ctor 3ET (-IS3ET!$ Comared to the -OS

caacitor" the -OS3ET incl'des two additional terminals (so'rce and drain!" each connected to

indiid'al hi%hl# doed re%ions that are searated b# the bod# re%ion$ These re%ions can be

either or n t#e" b't the# m'st both be of the same t#e" and of oosite t#e to the bod#

re%ion$ The so'rce and drain ('nli*e the bod#! are hi%hl# doed as si%nified b# a BKB si%n after the

t#e of doin%$

If the -OS3ET is an n=channel or n-OS 3ET" then the so'rce and drain are BnKB re%ions

and the bod# is a BB re%ion$ /s described aboe" with s'fficient %ate olta%e" holes from the bod#

are drien awa# from the %ate" formin% an inersion la#er or n=channel at the interface between

the re%ion and the o:ide$ This cond'ctin% channel e:tends between the so'rce and the drain"

and c'rrent is cond'cted thro'%h it when a olta%e is alied between so'rce and drain$

Increasin% the olta%e on the %ate leads to a hi%her electron densit# in the inersion la#er and

therefore increases the c'rrent flow between the so'rce and drain$

3or %ate olta%es below the threshold al'e" the channel is li%htl# o'lated" and onl# a

er# small s'b threshold lea*a%e c'rrent can flow between the so'rce and the drain$

If the -OS3ET is a =channel or -OS 3ET" then the so'rce and drain are BKB re%ions

and the bod# is a BnB re%ion$ When a ne%atie %ate=so'rce olta%e (ositie so'rce=%ate! is

alied" it creates a =channel at the s'rface of the n re%ion" analo%o's to the n=channel case" b't

with oosite olarities of char%es and olta%es$

When a olta%e less ne%atie than the threshold al'e (a ne%atie olta%e for =channel!

is alied between %ate and so'rce" the channel disaears and onl# a er# small s'b threshold

c'rrent can flow between the so'rce and the drain$


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The so'rce is so named beca'se it is the so'rce of the char%e carriers (electrons for n=

channel" holes for =channel! that flow thro'%h the channel> similarl#" the drain is where the

char%e carriers leae the channel$

The deice ma# comrise a Silicon On Ins'lator (SOI! deice in which a 5'ried OMide(5OM! is formed below a thin semicond'ctor la#er$ If the channel re%ion between the %ate

dielectric and a 5'ried O:ide (5OM! re%ion is er# thin" the er# thin channel re%ion is referred

to as an Ultra Thin Channel (UTC! re%ion with the so'rce and drain re%ions formed on either

side thereof in and,or aboe the thin semicond'ctor la#er$ /lternatiel#" the deice ma#

comrise a Semicond'ctor On Ins'lator (SE-OI! deice in which semicond'ctors other than

silicon are emlo#ed$ -an# alternatie semicond'ctor materials ma# be emlo#ed$

78$ -ULTILE0EL CON0ERTER1

/n inerter is an electrical deice that conerts direct c'rrent(DC! to alternatin% c'rrent

(/C!> the conerted /C can be at an# re&'ired olta%e and fre&'enc# with the 'se of aroriate

transformers" switchin%" and control circ'its$

Static inerters hae no moin% arts and are 'sed in a wide ran%e of alications" from

small switchin% ower s'liesin com'ters" to lar%e electric 'tilit#hi%h=olta%e direct c'rrent

alications that transort b'l* ower$ Inerters are commonl# 'sed to s'l# /C ower from

DC so'rces s'ch as solar anelsorbatteries$

The electrical inerter is a hi%h=ower electronic oscillator$ It is so named beca'se earl#

mechanical /C to DC conerterswas made to wor* in reerse" and th's were inerted" to

conert DC to /C$

The inerter erforms the oosite f'nction of a rectifier

C/SC/DED +=5RID;ES IN0ERTER

/ sin%le=hase str'ct're of an m=leel cascaded inerter is ill'strated in 3i%'re A7$7$

Each searate dc so'rce (SDCS! is connected to a sin%le=hase f'll=brid%e" or +=brid%e" inerter$
http://en.wikipedia.org/wiki/Direct_currenthttp://en.wikipedia.org/wiki/Alternating_currenthttp://en.wikipedia.org/wiki/Switched-mode_power_supplyhttp://en.wikipedia.org/wiki/Electric_utilityhttp://en.wikipedia.org/wiki/High-voltage_direct_currenthttp://en.wikipedia.org/wiki/Solar_panelhttp://en.wikipedia.org/wiki/Battery_(electrical)http://en.wikipedia.org/wiki/Battery_(electrical)http://en.wikipedia.org/wiki/Electronic_oscillatorhttp://en.wikipedia.org/wiki/Mechanical_rectifierhttp://en.wikipedia.org/wiki/Rectifierhttp://en.wikipedia.org/wiki/Direct_currenthttp://en.wikipedia.org/wiki/Alternating_currenthttp://en.wikipedia.org/wiki/Switched-mode_power_supplyhttp://en.wikipedia.org/wiki/Electric_utilityhttp://en.wikipedia.org/wiki/High-voltage_direct_currenthttp://en.wikipedia.org/wiki/Solar_panelhttp://en.wikipedia.org/wiki/Battery_(electrical)http://en.wikipedia.org/wiki/Electronic_oscillatorhttp://en.wikipedia.org/wiki/Mechanical_rectifierhttp://en.wikipedia.org/wiki/Rectifier


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Each inerter leel can %enerate three different olta%e o't'ts" K0dc" 8" and .0dcb# connectin%

the dc so'rce to the ac o't't b# different combinations of the fo'r switches" S7" S


13/35

O't't hase olta%e waeform of an 77=leel cascade inerter with searate dc so'rces$

The ma%nit'des of the 3o'rier coefficients when normali4ed with resect to 0dc are as follows1

The cond'ctin% an%les" 7"


14/35

Pen%


15/35

The series of +=brid%es ma*es for mod'lari4ed la#o't and ac*a%in%$ This will enable

the man'fact'rin% rocess to be done more &'ic*l# and cheal#$

DIS/D0/NT/;ES1

Searate dc so'rces are re&'ired for each of the +=brid%es$ This will limit its alication

to rod'cts that alread# hae m'ltile SDCSs readil# aailable$

DIODE=CL/-PED -ULTILE0EL IN0ERTER

The ne'tral oint conerter roosed b# Nabae" Ta*ahashi" and /*a%i in 7F7 was

essentiall# a three=leel diode=clamed inerter$ In the 7FF8s seeral researchers 'blished

articles that hae reorted e:erimental res'lts for fo'r=" fie=" and si:=leel diode=clamed

conerters for s'ch 'ses as static 0/R comensation" ariable seed motor dries" and hi%h=

olta%e s#stem interconnections$

/ three=hase si:=leel diode=clamed inerter is shown in 3i%'re$ Each of the three

hases of the inerter shares a common dc b's" which has been s'bdiided b# fie caacitors

into si: leels$ The olta%e across each caacitor is 0dc" and the olta%e stress across each

switchin% deice is limited to 0dc thro'%h the clamin% diodes$ Table lists the o't't olta%e

leels ossible for one hase of the inerter with the ne%atie dc rail olta%e 08 as a reference$State condition 7 means the switch is on" and 8 means the switch is off$ Each hase has fie

comlementar# switch airs s'ch that t'rnin% on one of the switches of the air re&'ires that the

other comlementar# switch be t'rned off$ The comlementar# switch airs for hase le% a are

(Sa7" Sa@7!" (Sa


16/35

Three=hase si:=leel str'ct're of a diode=clamed inerter$

Diode=clamed si:=leel inerter olta%e leels and corresondin% switch states$

/D0/NT/;ES1


17/35

/ll of the hases share a common dc b's" which minimi4es the caacitance re&'irements

of the conerter$ 3or this reason" a bac*=to=bac* toolo%# is not onl# ossible b't also

ractical for 'ses s'ch as a hi%h=olta%e bac*=to=bac* inter=connection or an ad)'stable

seed drie$

The caacitors can be re=char%ed as a %ro'$

Efficienc# is hi%h for f'ndamental fre&'enc# switchin%$

DIS/D0/NT/;ES1

Real ower flow is diffic'lt for a sin%le inerter beca'se the intermediate dc leels will

tend to oerchar%e or dischar%e witho't recise monitorin% and control$

The n'mber of clamin% diodes re&'ired is &'adratic all# related to the n'mber of leels"

which can be c'mbersome for 'nits with a hi%h n'mber of leels$

3L6IN; C/P/CITOR -ULTILE0EL IN0ERTER

-e#nard and 3och introd'ced a fl#in%=caacitor=based inerter in 7FF< $ The str'ct're of this

inerter is similar to that of the diode=clamed inerter e:cet that instead of 'sin% clamin%

diodes" the inerter 'ses caacitors in their lace$ The circ'it toolo%# of the fl#in% caacitor

m'ltileel inerter is shown in 3i%'re A7$$ This toolo%# has a ladder str'ct're of dc side

caacitors" where the olta%e on each caacitor differs from that of the ne:t caacitor$ The

olta%e increment between two ad)acent caacitor le%s %ies the si4e of the olta%e stes in the

o't't waeform$


18/35

Three=hase si:=leel str'ct're of a fl#in% caacitor inerter$

One adanta%e of the fl#in%=caacitor=based inerter is that it has red'ndancies for inner

olta%e leels> in other words" two or more alid switch combinations can s#nthesi4e an o't't

olta%e$ Table A7$< shows a list of all the combinations of hase olta%e leels that are ossible

for the si:=leel circ'it shown in 3i%'re A7$$ Unli*e the diode=clamed inerter" the fl#in%=

caacitor inerter does not re&'ire all of the switches that are on (cond'ctin%! be in a consec'tie

series$

-oreoer" the fl#in%=caacitor inerter has hase red'ndancies" whereas the diode=

clamed inerter has onl# line=line red'ndancies$ These red'ndancies allow a choice of

char%in%,dischar%in% secific caacitors and can be incororated in the control s#stem for

balancin% the olta%es across the ario's leels$

In addition to the (m=7! dc lin* caacitors" the m=leel fl#in%=caacitor m'ltileel

inerter will re&'ire (m=7! (m=

the m'ltileel fl#in% caacitor is static 0/R %eneration$ The main adanta%es and disadanta%es

of m'ltileel fl#in% caacitor conerters are as follows$


19/35

/D0/NT/;ES1

Phase red'ndancies are aailable for balancin% the olta%e leels of the caacitors$

Real and reactie ower flow can be controlled$

The lar%e n'mber of caacitors enables the inerter to ride thro'%h short d'ration o'ta%es

and dee olta%e sa%s$

DIS/D0/NT/;ES1

Control is comlicated to trac* the olta%e leels for all of the caacitors$ /lso"

rechar%in% all of the caacitors to the same olta%e leel and start' are comle:$

Switchin% 'tili4ation and efficienc# are oor for real ower transmission$

The lar%e n'mbers of caacitors are both more e:ensie and b'l*# than clamin% diodes

in m'ltileel diode=clamed conerters$ Pac*a%in% is also more diffic'lt in inerters with a hi%h

n'mber of leels$


20/35

78$G PULSE WIDT+ -ODUL/TION (PW-!1

P'lse Width -od'lation (PW-! is the most effectie means to achiee constant olta%e

batter# char%in% b# switchin% the solar s#stem controller@s ower deices$ When in PW-

re%'lation" the c'rrent from the solar arra# taers accordin% to the batter#@s condition andrechar%in% needs Consider a waeform s'ch as this1 it is a olta%e switchin% between 8 and

7


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5# ar#in% = or Bmod'latin%B = the time that the o't't is at 7


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Traditional solenoid drier electronics rel# on linear control" which is the alication of a

constant olta%e across a resistance to rod'ce an o't't c'rrent that is directl# roortional to

the olta%e$ 3eedbac* can be 'sed to achiee an o't't that matches e:actl# the control si%nal$

+oweer" this scheme dissiates a lot of ower as heat" and it is therefore er# inefficient$

/ more efficient techni&'e emlo#s 'lse width mod'lation (PW-! to rod'ce the

constant c'rrent thro'%h the coil$ / PW- si%nal is not constant$ Rather" the si%nal is on for art

of its eriod" and off for the rest$ The d't# c#cle" D" refers to the ercenta%e of the eriod for

which the si%nal is on$ The d't# c#cle can be an#where from 8" the si%nal is alwa#s off" to 7"

where the si%nal is constantl# on$ / 8 D res'lts in a erfect s&'are wae$ (3i%'re 7!

/ solenoid is a len%th of wire wo'nd in a coil$ 5eca'se of this confi%'ration" the solenoid

has" in addition to its resistance" R" a certain ind'ctance" L$ When a olta%e" 0" is alied across

an ind'ctie element" the c'rrent" I" rod'ced in that element does not )'m ' to its constant

al'e" b't %rad'all# rises to its ma:im'm oer a eriod of time called the rise time (3i%'re

Conersel#" I does not disaear instantaneo'sl#" een if 0 is remoed abr'tl#" b't decreases

bac* to 4ero in the same amo'nt of time as the rise time$


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Therefore" when a low fre&'enc# PW- olta%e is alied across a solenoid" the c'rrent

thro'%h it will be increasin% and decreasin% as 0 t'rns on and off$ If D is shorter than the rise

time" I will neer achiee its ma:im'm al'e" and will be discontin'o's since it will %o bac* to

4ero d'rin% 0@s off eriod (3i%'re A!$ In contrast" if D is lar%er than the rise time" I will neer

fall bac* to 4ero" so it will be contin'o's" and hae a DC aera%e al'e$ The c'rrent will not be

constant" howeer" b't will hae a rile$


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/t hi%h fre&'encies" 0 t'rns on and off er# &'ic*l#" re%ardless of D" s'ch that the

c'rrent does not hae time to decrease er# far before the olta%e is t'rned bac* on$ The

res'ltin% c'rrent thro'%h the solenoid is therefore considered to be constant$ 5# ad)'stin% the D"

the amo'nt of o't't c'rrent can be controlled$ With a small D" the c'rrent will not hae m'ch

time to rise before the hi%h fre&'enc# PW- olta%e ta*es effect and the c'rrent sta#s constant$

With a lar%e D" the c'rrent will be able to rise hi%her before it becomes constant$

W+6 T+E PW- 3REJUENC6 IS I-PORT/NT1

The PW- is a lar%e amlit'de di%ital si%nal that swin%s from one olta%e e:treme to theother$ /nd" this wide olta%e swin% ta*es a lot of filterin% to smooth o't$ When the PW-

fre&'enc# is close to the fre&'enc# of the waeform that #o' are %eneratin%" then an# PW-

filter will also smooth o't #o'r %enerated waeform and drasticall# red'ce its amlit'de$ So" a

%ood r'le of th'mb is to *ee the PW- fre&'enc# m'ch hi%her than the fre&'enc# of an#

waeform #o' %enerate$

3inall#" filterin% 'lses is not )'st abo't the 'lse fre&'enc# b't abo't the d't# c#cle and

how m'ch ener%# is in the 'lse$ The same filter will do better on a low or hi%h d't# c#cle 'lsecomared to a 8 d't# c#cle 'lse$ 5eca'se the wider 'lse has more time to inte%rate to a

stable filter olta%e and the smaller 'lse has less time to dist'rb it the insiration was a re&'est

to control the seed of a lar%e ositie dislacement f'el 'm$ The 'm was si4ed to allow f'll

ower of a boosted en%ine in e:cess of G88 +$


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/t idle or hi%hwa# cr'ise" this same en%ine needs far less f'el #et the 'm still normall#

s'lies the same amo'nt of f'el$ /s a res'lt the f'el %ets rec#cled bac* to the f'el tan*"

'nnecessaril# heatin% the f'el$ This PW- controller circ'it is intended to r'n the 'm at a low

seed settin% d'rin% low ower and allow f'll 'm seed when needed at hi%h en%ine ower

leels$

PW- CONTROLLER 3E/TURES1

This controller offers a basic V+i Seed and VLow Seed settin% and has the otion to

'se a VPro%ressie increase between Low and +i seed$ Low Seed is set with a trim ot inside

the controller bo:$ Normall# when installin% the controller" this seed will be set deendin% on

the minim'm seed,load needed for the motor$ Normall# the controller *ees the motor at this

Lo Seed e:cet when Pro%ressie is 'sed and when +i Seed is commanded (see below!$ LowSeed can ar# an#where from 8 PW- to 788$

Pro%ressie control is commanded b# a 8= olt in't si%nal$ This starts to increase PW-

from the low seed settin% as the 8= olt si%nal climbs$ This si%nal can be %enerated from a

throttle osition sensor" a -ass /ir 3low sensor" a -anifold /bsol'te Press're sensor or an#

other wa# the 'ser wants to create a 8= olt si%nal$ This f'nction co'ld be set to increase f'el

'm ower as t'rbo boost starts to climb (-/P sensor!$ Or" if controllin% a water in)ection

'm" Low Seed co'ld be set at 4ero PW- and as the TPS si%nal climbs it co'ld increasePW-" effectiel# increasin% water flow to the en%ine as en%ine load increases$

This controller co'ld een be 'sed as a secondar# in)ector drier (seeral in)ectors co'ld

be drien in a batch mode" hi imedance onl#!" with Pro%ressie control (8=788! #o' co'ld

control their o't't for f'el or water with the 8= olt si%nal$

Pro%ressie control adds enormo's fle:ibilit# to the 'se of this controller$ +i Seed is

that same as hard wirin% the motor to a stead# 7< olt DC so'rce$ The controller is roidin%788 PW-" stead# 7< olt DC ower$ +i Seed is selected three different wa#s on this

controller1 7! +i Seed is a'tomaticall# selected for abo't one second when ower %oes on$ This

%ies the motor f'll tor&'e at the start$ If needed this time can be increased ( the al'e of C7

wo'ld need to be increased!$

Seed si%nal wire$ This %ies +i Seed re%ardless of the Pro%ressie si%nal$


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SINUSOID/L PULSE WIDT+ -ODUL/TION1

In man# ind'strial alications" Sin'soidal P'lse Width -od'lation (SPW-!" also called

Sine coded P'lse Width -od'lation" is 'sed to control the inerter o't't olta%e$ SPW-

maintains %ood erformance of the drie in the entire ran%e of oeration between 4ero and ercent of the al'e that wo'ld be reached b# s&'are=wae oeration$ If the mod'lation inde:

e:ceeds this al'e" linear relationshi between mod'lation inde: and o't't olta%e is not

maintained and the oer=mod'lation methods are re&'ired

SP/CE 0ECTOR PULSE WIDT+ -ODUL/TION1

/ different aroach to SPW- is based on the sace ector reresentation of olta%es in

the d" & lane$ The d" & comonents are fo'nd b# Par* transform" where the total ower" as well

as the imedance" remains 'nchan%ed$

3i%1 sace ector shows sace ectors in accordin% to switchin% ositions of inerter"

0 is the hase=to=center olta%e which is obtained b# roer selection of ad)acent ectors 07

and 0


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Determination of Switchin% times

The reference sace ector 0 is %ien b# E&'ation (7!" where T7" T< are the interals of

alication of ector 07 and 0< resectiel#" and 4ero ectors 08 and 0 are selected for T8$

0 T4 07 T7 K 0< T< K 08 (T8,

SP/CE 0ECTOR PULSE WIDT+ -ODUL/TION (CONTINUED!

3i%$ below shows that the inerter switchin% state for the eriod T7 for ector 07 and for

ector 0


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CO-P/RISON

In 3i%1= comarison" U is the hase to= center olta%e containin% the trile order

harmonics that are %enerated b# sace ector PW-" and U7 is the sin'soidal reference olta%e$

5't the trile order harmonics are not aeared in the hase=to=hase olta%e as well$ This leadsto the hi%her mod'lation inde: comared to the SPW-$

CO-P/RISON O3 SPW- /ND SP/CE 0ECTOR PW-

/s mentioned aboe" SPW- onl# reaches to ercent of s&'are wae oeration" b't the

amlit'de of ma:im'm ossible olta%e is F8 ercent of s&'are=wae in the case of sace ector

PW-$ The ma:im'm hase=to=center olta%e b# sin'soidal and sace ector

PW- are resectiel#

0ma: 0dc,< 1 Sin'soidal PW-

0ma: 0dc,YA 1 Sace 0ector PW-

Where" 0dc is DC=Lin* olta%e$

This means that Sace 0ector PW- can rod'ce abo't 7 ercent hi%her than

Sin'soidal PW- in o't't olta%e$


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S0- PW- TEC+NIJUE1

The P'lse Width mod'lation techni&'e ermits to obtain three hase s#stem olta%es"

which can be alied to the controlled o't't$ Sace 0ector -od'lation (S0-! rincile differs

from other PW- rocesses in the fact that all three drie si%nals for the inerter will be created

sim'ltaneo'sl#$ The imlementation of S0- rocess in di%ital s#stems necessitates less

oeration time and also less ro%ram memor#$

The S0- al%orithm is based on the rincile of the sace ector '" which describes all

three o't't olta%es 'a" 'b and 'c 1

'


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Where a =7,< K ) $ A,< We can distin%'ish si: sectors limited b# ei%ht discrete ectors

'8X' (fi%1= inerter o't't olta%e sace ector!" which corresond to the D'rin% a switchin% eriod Tc and considerin% for e:amle the first sector" the ectors '8"

'7 and '< will be switched on alternatiel#$


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Definition of the Sace ector

Deendin% on the switchin% times t8" t7 and t< the sace ector ' is defined as1

' 7,Tc $ ( t8 $ '8 K t7 $ '7 K t< $ '< !

' t8 $ '8 K t7 $ '7 K t< $ '

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