Research Article FPGA Techniques Based New Hybrid ...downloads.hindawi.com/journals/tswj/2015/490151.pdfResearch Article FPGA Techniques Based New Hybrid Modulation Strategies for

Research ArticleFPGA Techniques Based New Hybrid Modulation Strategies forVoltage Source Inverters

L U Sudha1 J Baskaran2 and S A Elankurisil2

1Department of Electrical and Electronics Engineering ES Engineering College Villupuram 605602 India2Department of Electrical and Electronics Engineering Adhiparasakthi Engineering College Melmaruvathur 603319 India

Correspondence should be addressed to J Baskaran drbaski1rediffmailcom

Received 6 November 2014 Accepted 8 February 2015

Academic Editor Zhengyu Lin

Copyright copy 2015 L U Sudha et al This is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

This paper corroborates three different hybrid modulation strategies suitable for single-phase voltage source inverterThe proposedmethod is formulated using fundamental switching and carrier based pulse width modulation methods The main tale of thisproposed method is to optimize a specific performance criterion such as minimization of the total harmonic distortion (THD)lower order harmonics switching losses and heat losses The proposed method is articulated using fundamental switching andcarrier based pulse width modulation methods Thus the harmonic pollution in the power system will be reduced and the powerquality will be augmented with better harmonic profile for a target fundamental output voltageThe proposedmodulation strategiesare simulated in MATLAB r2010a and implemented in a Xilinx spartan 3E-500 FG 320 FPGA processor The feasibility of thesemodulation strategies is authenticated through simulation and experimental results

1 Introduction

Pulse width modulation (PWM) strategies are dedicated forpower converters to shape the output profile in a way benefi-cial to the industrial requirements There have been severalcontrol strategies developed to enhance the fundamentalcomponent and minimizing the total harmonics distortion(THD) through elimination of lower order harmonics andto create a wider dead band for a given switching frequency[1ndash3] Several attempts have been made in the last fewdecades to develop PWM schemes that differ in their conceptand performance [4ndash8] In 1999 an analog-based modifiedPWM control scheme has been developed to eliminate loworder harmonic components caused by the nonconstant dcvoltage [9] In 1981 a method has been enabled to obtainthe inverter output waveform variable continuously from anearly sinusoidal to square wave and aimed at increasing theamplitude of the output fundamental without further adverseeffects [10] Harmonic elimination using Walsh function hasbeen presented in [11] to cover optimized switching angles bysolving linear algebraic equations instead of solving nonlineartranscendental equationsThe THD optimization pattern hasbeen reported in [12ndash14] presenting amethod to eliminate theselected harmonics

This paper corroborates three different hybrid modula-tionmethods suitable for single-phase voltage source inverterderived using concatenation of fundamental switching andcarrier based pulse width modulation (PWM) methods likeunipolar PWM inverted sine carrier PWM and sixty-degreePWM respectively Consequently with better harmonic pro-file for a target fundamental output voltage the harmonicpollution in the power system will be moderated and thepower quality will be improved

2 Traditional PWM Methods

The PWM schemes developed for single-phase invertersshown in Figure 1 are used to improve the output pro-file through proposing carrier and reference modificationsBased on the detailed study few of the traditional PWMstrategies are discussed in this section In unipolar switchingscheme the output voltage level changes either between 0and minus119881119889 or from 0 to +119881119889 This scheme ldquoeffectivelyrdquo has theeffect of doubling the switching frequency as far as the outputharmonics are concerned compared to the bipolar-switchingscheme

Similar to unipolar PWM the voltage switches betweentwo levels minus119881119889 and +119881119889 the scheme is called the bipolar

Hindawi Publishing Corporatione Scientific World JournalVolume 2015 Article ID 490151 6 pageshttpdxdoiorg1011552015490151

2 The Scientific World Journal

S1

S2

S3

S4

VoutVdc

Figure 1 Single-phase inverter

PWM In this scheme the diagonally opposite transistors areturned on or turned off at the same time For a full-bridgeinverter with bipolar PWM scheme the output voltage isbetween minus1198811198892 and 1198811198892

The inverted sine carrier PWM (ISCPWM) controlscheme for single-phase full-bridge inverter eliminates pooroutput voltage spectral quality and reduced fundamentaloutput voltage It enhances the fundamental output voltageparticularly at lower modulation index ranges while keepingthe total harmonic distortion (THD) lower without involvingchanges in device switching losses

The 60-degree PWM is similar to the modified pwmTheidea behind 60-degree PWM is to ldquoflat toprdquo the waveformfrom 60 degrees to 120 degrees and 240 degrees to 300degrees The power devices are held on for one-third of thecycle (when at full voltage) and have reduced switching lossesThe 60-degree PWM creates a large fundamendal (23) andutilizes more of available dc voltage than does sinusoidalPWM The output waveform can be approximated by thefundamental and the first few terms

3 Proposed Hybrid Modulation Methods

The main philosophy of the PWM modulation emphasizesproviding desired fundamentalmagnitude and reduced THDby pushing the lower order harmonics to higher carrier bandthereby minimizing the filter design In this direction anew PWM strategy is developed to offer lesser switchingloss with improved harmonic profile while offering desiredfundamental output voltage The proposed hybrid pulsewidth modulation (HPWM) strategies shown in Figure 2 arethe amalgamation of fundamental frequency switching (FFS)and carrier based PWM(CBPWM) as a result that the outputpattern acceded to the texture of switching-loss reductionfrom FFS and better harmonic profile from CBPWM

The hybrid switching controller (HSC) basically consistsof logic circuits generating gating signal for each device withtwo different frequencies quarter cycle being switched atFFS while the other quarter cycle is modulated at CBPWMA random switching scheme is embedded with this hybridmodulation in order to swap both FFS andCBPWM for every

quarter cycle of the output waveform A simple base PWMcirculation scheme is also introduced here to get resultanthybrid PWM circulation that inherits the characteristics ofCBPWM methods The hybrid modulation scheme consistsof base PWM circulation and hybrid switching controller(HSC) to generate new modulation pulses

The block diagram representation of base PWM circu-lation design is seen in Figure 2 It is basically a PWMgeneration (119883 and 1198831015840) acquired from a direct comparisonof reference sine and carrier waveforms Based on the selec-tion of carrier the PWM generation is classified as hybridunipolar pulse width modulation (HUPWM) obtained fromthe comparison between sine reference and unipolar carrierwhile hybrid inverted sine carrier pulse width modulation(HISCPWM) for inverter module is generated from theinverted sine carrier The other PWM method reported forfundamental enhancement with improved harmonic profilenamely H-60∘ PWM (HSDPWM)

In addition to PWM circulation pulses the HPWMrequires three square wave signals that make every powerswitch operating at carrier based PWM (CBPWM) andsquarewave randomly per quarter cycle to equalize the powerlosses within each device Two signals are random switchingpulse (119862 and 119884) out of three square wave signals having50 duty ratio and frequencies with half and twice thefundamental frequencyThe third signal is FFS (119860) a square-wave signal synchronized with the reference sine waveform(119860 = 1) during the positive and (119860 = 0) during negative halfcycles of the reference sine

HSC combines random signals (119884 and 119862) FFS (119860) andCBPWM (119883 and1198831015840) that produces hybridmodulation (HM)pulses It is designed by using a simple combinational logicand the functions for a single-phase inverter are expressed as

1198781 = (119884 sdot 119862 + 119884 sdot 119862) sdot 119860 + 119883 (1)

1198782 = (119884 sdot 119862 + 119884 sdot 119862) sdot 119860 + 119883 (2)

1198783 = (119884 sdot 119862 + 119884 sdot 119862) sdot 119860 + 1198831015840 (3)

1198784 = (119884 sdot 119862 + 119884 sdot 119862) ∙ 119860 + 1198831015840 (4)

HSC controller constituted using equations (1) to (4) eachgate signal is composed of both low and high frequencysignals If 119860 = 1 S1 and S2 are commutated at low frequencyin the first and second quarter of first half cycle whileboth devices are modulated with PWM in the second andfirst quarter cycles in the same half cycle of fundamentalfrequency respectively Similarly if 119860 = 0 S3 and S4 aremodulated with the same pattern in the second half cycle ofthe fundamental frequency as those in the devices S1 and S2respectivelyTherefore voltage stress and current stress of fourswitches are also equalized The proposed HPWM methodallows use of similar power devices with identical heat sinksthus permitting a more reliable design

The Scientific World Journal 3

Pulse generation for

Fundamental

Comparator

Comparator

Modulationwaveform

Y

C

A

X

X998400

minus

Am

Ac

Vc

Carrier waveform

quarter cycle swapping

Pulse generation for full cycle swapping

frequency PWM

generation

2f0

f0

f02

(a) Hybrid UPWM (HUPWM)

Comparator

Comparator

Modulationwaveform

Y

C

A

X

X998400

minus

Pulse generation for quarter cycle swapping


Fundamental frequency

PWM generation

Am

Ac

Vc

2f0

f0

f02

(b) Hybrid ISCPWM (HISCPWM)

Comparator

Comparator

Y

C

A

X

X998400

Modulationwaveform

Am

Ac

Vc

Carrier waveform




PWM generation

minus

2f0

f0

f02

(c) Hybrid 60∘ PWM (H-60∘ PWM)

Figure 2 Proposed hybrid strategies

200

100

0

minus100

minus2000 0005 001 0015 002 0025 003 0035 004

Time (s)

(a)

100

80

60

40

20

00 50 100 150 200 250 300

Fundamental (50Hz) = 1606 THD = 7453

Mag

(

of f

unda

men

tal)

Harmonic order

(b)

Figure 3 Proposed Hybrid UPWM (HUPWM)


200

100

0

minus100

minus2000 0005 001 0015 002 0025 003 0035 004

Time (s)

(a)

100

80

60

40

20

00 50 100 150 200 250 300

Mag

(

of f

unda

men

tal)

Harmonic order


(b)

Figure 4 Proposed Hybrid ISCPWM (HISCPWM)

200

100

0

minus100

minus2000 0005 001 0015 002 0025 003 0035 004

Time (s)

(a)

100

80

60

40

20

00 50 100 150 200 250 300

Mag

(

of f

unda

men

tal)

Harmonic order


(b)

Figure 5 Proposed Hybrid 60∘ PWM (H-60∘ PWM)

200

180

160

140

120

100

80

60

40

20

0

02 04 06 08 1

Modulation depth

Fund

amen

tal o

utpu

t vol

tage

(V)

HUPWMHISCPWMHSDPWM

Figure 6 Fundamental output voltage against modulation depth


(a) (b) (c)

Figure 7 HUPWM (a) pulse pattern (b) output voltage waveform and (c) harmonic spectrum

(a) (b) (c)

Figure 8 HISCPWM (a) pulse pattern (b) output voltage waveform and (c) harmonic spectrum

4 Simulation Results

In order to evaluate the quality of output voltage waveformacquired from single-phase inverter using the proposedHPWM methods the simulation study is carried in MAT-LABSimulink platformThe input parameters for simulationstudy are taken with dc-link voltage (119881dc) = 200V switchingfrequency of PWM signal (119891119904) = 1 kHz fundamentalfrequency (1198910) = 50Hz 119877 = 150Ω and 119871 = 100mHrespectively

Thorough simulation study has been carried out forsingle-phase inverter by keeping 119872119886 = 08 for all theproposed hybrid modulation methods It is evident fromFigures 3 to 5 result thatHUPWMproduces 191 V (peak) withTHD of 6435 and HISCPWM offers fundamental voltageof 1977 V (peak) with THD of 4853

Figure 6 shows the variation of fundamental outputvoltage against modulation depth It is authenticated that thefundamental voltage goes on increasing as the modulationdepth approaches 1 HSDPWM have more fundamental out-put voltage compared with HUPWM for a given modulationdepth as depicted in the same Figure 6 and similarly it isseen that the H-60∘ PWM offers lesser THD with increase inmodulation depth

5 Experimental Results

The hardware rig is constituted using MOSFETs (IRF 840)laboratory variable dc-link voltage setup and resistive-inductive load of R = 100Ω and 119871 = 100mH The control

algorithm is implemented in Xilinx Spartan 3E-500 FG320 field programmable gate array (FPGA) processor Itincorporates a facility to be either configured or reconfiguredby the application engineer The Spartan 3E-500 FG 320 hason-board high-speed USB port 500K logic gates 16MB ofPSDRAM 16MB of Intel strata flash ROM and 60 FPGAinputoutput routed to expansion connectors Xilinx offersCAD tools for the development of ASIC based FPGA andVHDL is used in digital logic design The algorithm is thencomplied and simulated usingModelsim softwareThe bit fileis generated in Xilinx software and finally downloaded to theSpartan 3Edevice throughUSB cableThedownloaded pulsesare applied to single-phase inverter to produce the PWMmodulated output voltage waveform The download pulsesload output voltage waveform along with voltage spectrumare captured through Tektronix TPS 2024 scope which isshown in Figures 7 to 9 respectively It is evident fromFigures 7 to 9 that the simulation outputs accorded with theexperimental results

6 Conclusion

VariousHPWMstrategies for single-phase inverter operatingat low switching frequency with lesser switching commuta-tions are proposed The proposed HPWM method can beextended to any carrier based PWMmethods In comparisonwith conventional PWM methods the proposed methodsoffer lesser number of switching commutations and reducedswitching loss for the same fundamental voltage The har-monic performance of the HPWMmethods are examined in


(a) (b) (c)

Figure 9 HSDPWM (a) pulse pattern (b) output voltage waveform and (c) harmonic spectrum

the entire operating range and its performance is better Theproposed methods facilitate balanced conduction loss withreduced switching loss within each device Also the hybridPWM strategy reduces conduction losses to a larger extent sothat the THD is better when compared to the conventionalPWM methods The experimental results demonstrate thatthe proposed methods can be extended to any type of dc-acac-ac power conversion systems

Conflict of Interests

The authors declare that there is no conflict of interestsregarding the publication of this paper

References

[1] R J Kerkman D Leggate B J Seibel and T M Rowan ldquoOper-ation of PWM voltage source-inverters in the overmodulationregionrdquo IEEE Transactions on Industrial Electronics vol 43 no1 pp 132ndash141 1996

[2] M A Boost and P D Ziogas ldquoState-of-the-art carrier PWMtechniques a critical evaluationrdquo IEEE Transactions on IndustryApplications vol 24 no 2 pp 271ndash280 1988

[3] J Holtz ldquoPulsewidthmodulationmdasha surveyrdquo IEEE Transactionson Industrial Electronics vol 39 no 5 pp 410ndash420 1992

[4] S Jeevananthan P Dananjayan and A Mohamed Asif FisalldquoA HPWM method for thermal management in a full-bridgeinverter with loss estimation and electro-thermal simulationrdquoAMSE Periodicals of Modeling Measurement and ControlmdashSeries B vol 73 no 6 pp 1ndash20 2004

[5] S Y R Hui S Sathiakumar and K-K Sung ldquoNovel randomPWM schemes with weighted switching decisionrdquo IEEE Trans-actions on Power Electronics vol 12 no 6 pp 945ndash952 1997

[6] Y M Chen and Y M Cheng ldquoPWM control using a modifiedtriangle signalrdquo IEEE Transactions on Industrial Electronics vol1 no 29 pp 312ndash317 1999

[7] P N Enjeti P D Ziogas and J F Lindsay ldquoProgrammedPWM techniques to eliminate harmonics a critical surveyrdquoIEEE Transactions on Industry Applications vol 26 no 2 pp302ndash316 1990

[8] S Vadivel G Bhuvaneswari and G S Rao ldquoA unifiedapproach to the real-time implementation of microprocessor-based PWMwaveformsrdquo IEEE Transactions on Power Electron-ics vol 6 no 4 pp 565ndash575 1991

[9] Y-M Chen and Y-M Cheng ldquoModified PWM control forthe DC-AC inverter with a non-constant voltage sourcerdquo inProceedings of the 3rd IEEE International Conference on PowerElectronics and Drive Systems (PEDS rsquo99) pp 938ndash941 IEEEHong Kong July 1999

[10] T-J Liang RMOrsquoConnell and R G Hoft ldquoInverter harmonicreduction usingWalsh function harmonic eliminationmethodrdquoIEEE Transactions on Power Electronics vol 12 no 6 pp 971ndash982 1997

[11] J M D Murphy and M G Egan ldquoA comparison of PWMstrategies for inverter fed induction motorsrdquo in Proceedings ofthe 17th Industry Applications Society 1982 Annual Meeting pp569ndash573

[12] S Mekhilef and N A Rahim ldquoXilinx FPGA based three-phasePWM inverter and its application for utility connected PVsystemrdquo in Proceedings of the IEEE Region 10 Conference onComputers Communications Control and Power Engineering(TENCON rsquo02) pp 2079ndash2082 October 2002

[13] M J Meco-Gutierrez A Ruiz Gonzalez F Vargas Merinoand J R Heredia-Larrubia Reduction in Induction MotorHeating Fedby a New PWMTechnique Results Obtained in Lab-oratory Experiments ETS Ingenieros Industriales Universi-dad de Malaga Malaga Spain httpwwwicrepqcomicrepq-08293 mecopdf

[14] S Jeevananthan P Dananjayan and S Venkatesan ldquoA novelmodified carrier PWM switching strategy for single-phase full-bridge inverterrdquo Iranian Journal of Electrical and ComputerEngineering vol 4 no 2 pp 101ndash108 2005

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Chemical EngineeringInternational Journal of Antennas and

Propagation




Navigation and Observation



DistributedSensor Networks



S1

S2

S3

S4

VoutVdc

Figure 1 Single-phase inverter

PWM In this scheme the diagonally opposite transistors areturned on or turned off at the same time For a full-bridgeinverter with bipolar PWM scheme the output voltage isbetween minus1198811198892 and 1198811198892

The inverted sine carrier PWM (ISCPWM) controlscheme for single-phase full-bridge inverter eliminates pooroutput voltage spectral quality and reduced fundamentaloutput voltage It enhances the fundamental output voltageparticularly at lower modulation index ranges while keepingthe total harmonic distortion (THD) lower without involvingchanges in device switching losses

The 60-degree PWM is similar to the modified pwmTheidea behind 60-degree PWM is to ldquoflat toprdquo the waveformfrom 60 degrees to 120 degrees and 240 degrees to 300degrees The power devices are held on for one-third of thecycle (when at full voltage) and have reduced switching lossesThe 60-degree PWM creates a large fundamendal (23) andutilizes more of available dc voltage than does sinusoidalPWM The output waveform can be approximated by thefundamental and the first few terms

3 Proposed Hybrid Modulation Methods

The main philosophy of the PWM modulation emphasizesproviding desired fundamentalmagnitude and reduced THDby pushing the lower order harmonics to higher carrier bandthereby minimizing the filter design In this direction anew PWM strategy is developed to offer lesser switchingloss with improved harmonic profile while offering desiredfundamental output voltage The proposed hybrid pulsewidth modulation (HPWM) strategies shown in Figure 2 arethe amalgamation of fundamental frequency switching (FFS)and carrier based PWM(CBPWM) as a result that the outputpattern acceded to the texture of switching-loss reductionfrom FFS and better harmonic profile from CBPWM

The hybrid switching controller (HSC) basically consistsof logic circuits generating gating signal for each device withtwo different frequencies quarter cycle being switched atFFS while the other quarter cycle is modulated at CBPWMA random switching scheme is embedded with this hybridmodulation in order to swap both FFS andCBPWM for every

quarter cycle of the output waveform A simple base PWMcirculation scheme is also introduced here to get resultanthybrid PWM circulation that inherits the characteristics ofCBPWM methods The hybrid modulation scheme consistsof base PWM circulation and hybrid switching controller(HSC) to generate new modulation pulses

The block diagram representation of base PWM circu-lation design is seen in Figure 2 It is basically a PWMgeneration (119883 and 1198831015840) acquired from a direct comparisonof reference sine and carrier waveforms Based on the selec-tion of carrier the PWM generation is classified as hybridunipolar pulse width modulation (HUPWM) obtained fromthe comparison between sine reference and unipolar carrierwhile hybrid inverted sine carrier pulse width modulation(HISCPWM) for inverter module is generated from theinverted sine carrier The other PWM method reported forfundamental enhancement with improved harmonic profilenamely H-60∘ PWM (HSDPWM)

In addition to PWM circulation pulses the HPWMrequires three square wave signals that make every powerswitch operating at carrier based PWM (CBPWM) andsquarewave randomly per quarter cycle to equalize the powerlosses within each device Two signals are random switchingpulse (119862 and 119884) out of three square wave signals having50 duty ratio and frequencies with half and twice thefundamental frequencyThe third signal is FFS (119860) a square-wave signal synchronized with the reference sine waveform(119860 = 1) during the positive and (119860 = 0) during negative halfcycles of the reference sine

HSC combines random signals (119884 and 119862) FFS (119860) andCBPWM (119883 and1198831015840) that produces hybridmodulation (HM)pulses It is designed by using a simple combinational logicand the functions for a single-phase inverter are expressed as

1198781 = (119884 sdot 119862 + 119884 sdot 119862) sdot 119860 + 119883 (1)

1198782 = (119884 sdot 119862 + 119884 sdot 119862) sdot 119860 + 119883 (2)

1198783 = (119884 sdot 119862 + 119884 sdot 119862) sdot 119860 + 1198831015840 (3)

1198784 = (119884 sdot 119862 + 119884 sdot 119862) ∙ 119860 + 1198831015840 (4)

HSC controller constituted using equations (1) to (4) eachgate signal is composed of both low and high frequencysignals If 119860 = 1 S1 and S2 are commutated at low frequencyin the first and second quarter of first half cycle whileboth devices are modulated with PWM in the second andfirst quarter cycles in the same half cycle of fundamentalfrequency respectively Similarly if 119860 = 0 S3 and S4 aremodulated with the same pattern in the second half cycle ofthe fundamental frequency as those in the devices S1 and S2respectivelyTherefore voltage stress and current stress of fourswitches are also equalized The proposed HPWM methodallows use of similar power devices with identical heat sinksthus permitting a more reliable design



Fundamental

Comparator

Comparator

Modulationwaveform

Y

C

A

X

X998400

minus

Am

Ac

Vc

Carrier waveform



frequency PWM

generation

2f0

f0

f02


Comparator

Comparator

Modulationwaveform

Y

C

A

X

X998400

minus




PWM generation

Am

Ac

Vc

2f0

f0

f02


Comparator

Comparator

Y

C

A

X

X998400

Modulationwaveform

Am

Ac

Vc

Carrier waveform




PWM generation

minus

2f0

f0

f02



200

100

0

minus100

minus2000 0005 001 0015 002 0025 003 0035 004

Time (s)

(a)

100

80

60

40

20

00 50 100 150 200 250 300


Mag

(

of f

unda

men

tal)

Harmonic order

(b)



200

100

0

minus100

minus2000 0005 001 0015 002 0025 003 0035 004

Time (s)

(a)

100

80

60

40

20

00 50 100 150 200 250 300

Mag

(

of f

unda

men

tal)

Harmonic order


(b)


200

100

0

minus100

minus2000 0005 001 0015 002 0025 003 0035 004

Time (s)

(a)

100

80

60

40

20

00 50 100 150 200 250 300

Mag

(

of f

unda

men

tal)

Harmonic order


(b)


200

180

160

140

120

100

80

60

40

20

0

02 04 06 08 1

Modulation depth

Fund

amen

tal o

utpu

t vol

tage

(V)

HUPWMHISCPWMHSDPWM



(a) (b) (c)


(a) (b) (c)









6 Conclusion



(a) (b) (c)





References

















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation











Fundamental

Comparator

Comparator

Modulationwaveform

Y

C

A

X

X998400

minus

Am

Ac

Vc

Carrier waveform



frequency PWM

generation

2f0

f0

f02


Comparator

Comparator

Modulationwaveform

Y

C

A

X

X998400

minus




PWM generation

Am

Ac

Vc

2f0

f0

f02


Comparator

Comparator

Y

C

A

X

X998400

Modulationwaveform

Am

Ac

Vc

Carrier waveform




PWM generation

minus

2f0

f0

f02



200

100

0

minus100

minus2000 0005 001 0015 002 0025 003 0035 004

Time (s)

(a)

100

80

60

40

20

00 50 100 150 200 250 300


Mag

(

of f

unda

men

tal)

Harmonic order

(b)



200

100

0

minus100

minus2000 0005 001 0015 002 0025 003 0035 004

Time (s)

(a)

100

80

60

40

20

00 50 100 150 200 250 300

Mag

(

of f

unda

men

tal)

Harmonic order


(b)


200

100

0

minus100

minus2000 0005 001 0015 002 0025 003 0035 004

Time (s)

(a)

100

80

60

40

20

00 50 100 150 200 250 300

Mag

(

of f

unda

men

tal)

Harmonic order


(b)


200

180

160

140

120

100

80

60

40

20

0

02 04 06 08 1

Modulation depth

Fund

amen

tal o

utpu

t vol

tage

(V)

HUPWMHISCPWMHSDPWM



(a) (b) (c)


(a) (b) (c)









6 Conclusion



(a) (b) (c)





References

















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










200

100

0

minus100

minus2000 0005 001 0015 002 0025 003 0035 004

Time (s)

(a)

100

80

60

40

20

00 50 100 150 200 250 300

Mag

(

of f

unda

men

tal)

Harmonic order


(b)


200

100

0

minus100

minus2000 0005 001 0015 002 0025 003 0035 004

Time (s)

(a)

100

80

60

40

20

00 50 100 150 200 250 300

Mag

(

of f

unda

men

tal)

Harmonic order


(b)


200

180

160

140

120

100

80

60

40

20

0

02 04 06 08 1

Modulation depth

Fund

amen

tal o

utpu

t vol

tage

(V)

HUPWMHISCPWMHSDPWM



(a) (b) (c)


(a) (b) (c)









6 Conclusion



(a) (b) (c)





References

















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










(a) (b) (c)


(a) (b) (c)









6 Conclusion



(a) (b) (c)





References

















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation










(a) (b) (c)





References

















RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation











RoboticsJournal of





Journal of



RotatingMachinery





VLSI Design



Shock and Vibration







Journal of



Volume 2014


SensorsJournal of





Propagation









Documents

Research Article FPGA Techniques Based New Hybrid ...downloads.hindawi.com/journals/tswj/2015/490151.pdfResearch Article FPGA Techniques Based New Hybrid Modulation Strategies for