Digital Controller for the Mixed Conduction

7/21/2019 Digital Controller for the Mixed Conduction

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Design of Digital Control circuit

for power Power FactorCorrection in power

converters( Boost) and reductio

of EMISUBM

"#&''

(C%

Under t+e &uidance of ,Dr'M Ma+es+ ME-P+'D

Professor-Depart.ent of EEE-PESI/ - B"&"0O%E



Introduction Most of electrical and electronics e4uip.ent wor5ing on dc - w+ic+ get conn

.ains using diode recti7er at t+e input'

/+e non8linear nature of diode recti7er causes signi7cant line current +ar.onic

t+e6 degrade power 4ualit6- increases losses'

/+erefore- stringent international standard IEC 2***889 is i.posed to res

allowed /;D ;ence- +ar.onic reduction circuits .ust <e incorporate in Power E

Boost PFC converters wit+ digital controller is one of t+e .ost suita<le conver

power factor (PF) and decrease t+e total +ar.onic distortion (/;D) of its input c

"n adaptive control tec+ni4ue and DSP8<ased DCM detection .et+od to pr

control of t+e <oost PFC for wide range of load'



O<=ective of Pro=ect /o i.prove power 4ualit6 for <oost PFC converters operating in .i:ed co

For t+e "C8DC <oost PFC converter <6 introducing a novel digital >ero8cu

tec+ni4ue'

Several e:isting .et+ods to detect >ero inductor current e.plo6 co.ple:

and1or au:iliar6 circuit re4uire.ents for DCM detection-eit+er digital tec+

circuit'

;ig+ speed DSP co.parator is used to detect t+e >ero inductor current e

for costl6 au:iliar6 winding'

separate DCM and CCM average current .ode co.pensators are used -d

detected .ode of operation'



Power Factor:

?

@+ere 5A ? cosA is t+e displace.ent factor-

is distortion factor'

/+e displace.ent factor and distortion fact

relates /;D and power factor directl6 given<6



E:a.ples of dierent current s+apes s+ow t+edierent distortion factors and displace.ent

factors

(a) k θ <1, k d <1, (b) k θ =1, k

d <1

(c) k θ <1, k d =1, (d) k θ =1, k

d =1



Overall block diagram



Boost converter as a power factorcorrector

".ong 8<asic power converters <uc5- <oost- <uc58<oost- t+e <oost converter is

for use in i.ple.enting PFC'

Because series inductor will ac+ieve s.aller current ripple and easier to i.ple.e

current .ode control'

"dvantages of t+e <oost PFC converter includes

Its low cost and less co.ple:it6

;ig+ switc+ing fre4uencies- allowing a reduction in t+e p+6sical si>e of capacito



Operation of t+e PFC Boost Converte

Positive line input +alf8c6cle operation of t+e PFC <oost converter wit+ switc+ G cl0 isstoring energ6 and output capacitor C is disc+arging energ6 to load'

Sa.e positive line input +alf c6cle operation of t+e PFC <oost converter wit+ switc

Inductor 0 is suppl6ing energ6 to t+e load and c+arging C at a voltage greater t+avoltage'



@avefor.s of <oost converter



"verage Current Mode Control• The principle of average current mode control is to control the average inductor current I

L to be propo

to the rectified input voltage.

• Current tracking forces the average inductor current to track the current reference so that it has th

shape as the input voltage, as shown in Fig. This task gives the input a unity PF.



Types of Inductor CurrentModes



EIS/I& S!S/EM



PROPO!" #T!$



Small-signal Models for the CCM and CM !oost "#C

Converters

/+e lineari>ed s.all8signal .odel of t+e CCM <oost PFC control8to8output /ransfer function is given <6

/+e lineari>ed s.all8signal .odel of t+e DCM <oost PFC control8to8output

/ransfer function is given <6



C$rrent Com%ensator esign in CCM&

the designed continuous%time transfer function of the P& compensator is given by

The 'ilinear Transformation is used to transform the controller into a discrete e(uivalent, through t

transformation

S6ste. <loc5 diagra. of CCM <oost PFC converter



Discreti>ation of t+e CCM co.pensator wit+ t+e Bilinear /ransfor.ation is given <6

C$rrent Com%ensator esign in CM

In t+e sa.e fas+ion t+at t+e CCM current co.pensator was designed- t+e DCM

co.pensator is designed in M"/0"B to ac+ieve t+e desired response c+aracte

given <6



Design of Voltage Compensator

/+e control s6ste. includes a discrete proportional8integral voltage co.pensaw+ic+ regulates t+e converterJs output voltage



Sim$lation modal



Sim$lation 'es$lts



Sim$lation 'es$lts

&nput voltage at different loads.

output voltage wavefor. of Boost converter



voltage error

output of voltage co.pensator



%ecti7ed input voltage

%eference current



Boost Inductor Current wavefor.

current error



output wavefor. of co.parator for DCM detection'

output wavefor. fro. current co.pensators



/riangular carrier wavefor. for DP@M

P@M single for MOSFE/

switc+



(a) "t load 23*@ (<) "t load H@

Input current and input voltage at dierent loads



(a) "t load H@ (<) "t load 23*

/;D at dierent loads

Su..ar6 of power factor and /;D .easure.ents for various output power for



Conventional digital controller "ro%osed digital controller

"o$t(att) T)" *+ Power factor T)" *+ Power factor

* -./ 0.1234 4./4 0.1114

1+ 5.4 0.1161 /.36 0.1114

. 4.64 0.114 /.41 0.111

/+ /.1 0.114 /.45 0.1111

/. /.-- 0.11 /.01 0.1111

0++ /.65 0.111/ 0.11 0.1111

+. /.4- 0.1113 0.16 0.1111

+*+ /./5 0.1113 0.14 0.1111

+. /.06 0.113 0.10 0.1111

Su..ar6 of power factor and /;D .easure.ents for various output power for

eac+ of t+e Conventional Digital- and Proposed Digital Controllers (vac ? 9* #- f l

? 2* ;>)

COC0USIOS



• "s a contri<ution to +ig+84ualit6 input current for electronic devices- t+is

contri<uted control tec+ni4ues ena<ling i.prove.ents in power 4ualit6'

• In t+is regard- a novel adaptive MCM control tec+ni4ue for Boost PFC converter

wide load range +as <een presented'• In particular- a DCM detection .et+od +as <een proposed using DSP integr

t+ere<6 ena<ling si.pli7cation and cost8reduction over e:isting DCM and >ero

.et+ods'

• B6 using 5nowledge of t+e detected .ode of operation- MCM controller wa

appropriate CCM or DCM co.pensator selection for t+e detected .ode of operat

• I.prove.ents in power 4ualit6 <6 lowering /;D and i.proving power factor i

conventional digital control tec+ni4ue +as <een reali>ed <6 si.ulating pr

M"/0"B8SIMU0I$ environ.ent'



/+is section provides possi<le reco..endations to e:pand on t+e wor5

dissertation'

• /+e +ardware .odel of proposed s6ste. can <e i.ple.ented using /M

series DSP as a controller'

• Controller can <e designed wit+ still reduced Switc+ing Fre4uencies, wit

switc+ing speed- t+e DSP would +ave .ore ti.e to service t+e >ero8cu

and t+erefore provide potentiall6 greater power 4ualit6

Future scope



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Digital Controller for the Mixed Conduction