Sinusoidal pwm

Sinusoidal pulse with modulation technique

1. Sinusoidal PWM
Branch:-Electrical Engineering
Subject:-Power Electronics II
Presented by:-
Chintan Hansalia (151310109009)

2. Sinusoidal PWM
•Thewidthofallthepulsesarenotidentical.Insteadthe
pulsewidthisproportionaltotheinstantaneousamplitudeof
asinewave.
•ThePWMwaveformgeneratedisthenusedtodriveIGBTsor
othersemiconductordevicesconnectedintheinvertercircuit.
•Thefrequencyoftriangularwavedecidesthenumberof
pulsesintheoutputwaveformperhalfcycle.

3. •Thistypeofmodulationisrealizedbycomparingacontrol
signalconsistingofsinusoidalwaveofvariablemagnitudeA
m
&frequencyf
mandatriangularwaveoffixedamplitudeA
cand
frequencyf
c.
•Theperiodoftriangularwaveischosensuchthatintegralno.of
triangularpulsesexistpercycleofsinusoidalwaveform.

4. V
ref> V
car=> u(t) = +1

5. •ThemodulationindexofthePWMsignalisdefinedas,
??????=
??????�??????�??????���??????�������ℎ������??????�??????���??????��??????�
??????�??????�??????���??????�������ℎ��??????��??????���??????��??????�
=
A
m
A
c
•Theoutputvoltagechangedbychangingthemodulationindex
‘m’.
•Withm,pulsewidth,outputvoltage
•Thecarrierfrequencyratiois
m
f=
??????�������??????���ℎ��??????��??????���??????��??????�
??????�������??????���ℎ������??????�??????���??????��??????�
=
f
c
f
m

6. •Forharmonicreductionwehave,
b
n=
4??????�
п
1−2cos�α
2
+2����α
1
�
•Fortheremovalof3
rd
and5
th
harmonicswehavetotake
α
1=23.62°&α
2=33.3°

7. Advantages
•Noadditionalfiltersarerequiredfortheeliminationof
harmonics.
•TheperformanceofSPWMinvertersismuchbetter.
•Inputpowerfactordoesnotdependonvariationin
outputvoltage

8. Disadvantages
•Withincreaseinnumberofpulsespercycle,the
switchinglossestakingplaceinthepowerdevices
increase.
•Thevalueoffundamentalcomponentoftheoutput
voltageisonly70.7%oftheDCsupplyvoltage.

9. Thank You