Generation of Space Vector PWM Using Microcontroller Atmega · PDF fileGeneration of Space Vector PWM Using Microcontroller Atmega 16 ... (SVPWM) signals. The main feature of the research

Generation of Space Vector PWM UsingMicrocontroller Atmega 16

Slamet

Abstract— This paper describes the use of a microcontroller atmega 16 to generate the space vector pulse width modulation (SVPWM)signals. The main feature of the research is the simplicity of the hardware and easy to digitally programmed. Testing and analyzing systemis done at no load condition with varying carrier frequency, amplitude, and sinusoidal frequency. Varying carrier frequency is done byutilizing software with code vision AVR tools, while the amplitude and the sinusoidal frequency are varied by using potentiometers asanalog input data. Based on the results of testing and analyzing, it is shown that the SVPWM signals could be implemented withmicrocontroller Atmega 16 at carrier frequency 490 Hz and THD at sinusoidal frequency of 25Hz, 50Hz, and 100Hz is about 13.85%,23.89%, and 17.43%..

Index Terms— Space Vector PWM, microcontroller, software, varying carrier frequency, amplitude, sinusoidal frequency, analog input.

—————————— ——————————

1 INTRODUCTIONNowadays, harmonic pollution in electrical powersystems due to nonlinear loads such as Inverter powerconverter has become a serious problem. Inverter powerconverter is a voltage converter DC to AC with adjustablevoltage and output frequency so that applicable to controlthree phase AC induction motor. There are some invertertype between it is an inverter power converter with theSVPWM (Space Vector Pulse Width Modulation)[1].Advantage of technique SVPWM is very economic andpractical to be applied operation of three phase ACinduction motor. Besides if generation of signal SVPWMis done digitally will be able to be obtained system workshort exchange is more impenetrably to noise. Design of asignal generator SVPWM applies microcontroller to havesome advantages that is easy to be program and invertercircuit to become simple. To eliminate or reduceharmonics in the power systems, a number of methodshave been developed and put into practice. SVPWMmethods is used to generate active power filter. The activepower filter built fom SVPWM can be programmed withmicrocontroller. In this research using microcontrolleratmega 16 which is the local content. Therefore, we candesign a power converter to supply DC power to its ownload and, at the same time, operates as an active filter tosupply to the AC line a compensating current equal to theharmonic current produced by the nonlinear load

connected to the same AC line[3][4][5][6].

2 PRINCIPLE OF SVPWMThe principle of Space Vector PWM is based on the

fact that there are only eight possible switchcombinations for a three phase inverter. The basicinverter switch states are shown in Figure 1. Two ofthese states (SV0 and SV7) correspond to short circuitwhile the other six can be considered to formstationary vectors in the d-q plane as shown in Fig.2.The magnitude of each of the six active vectorscorresponding to the maximum possible phase voltageis:

23m dcV V (1)

Having identified the stationary vectors, at anypoint in time, an arbitrary target output voltage vectorcan then be made up by the summation (“averaging”)of the adjacent space vectors within one switchingperiod. Target vectors in the other five segments of thehexagon are clearly obtained in a similar manner. Thegeometric summation shown in Fig.2. can be expressedmathematically as [5],

1 2 0 0 0(cos ) (cos sin )3 3 2m m

TTsvV Tsv V jsin V j (2)

for each switching period ΔT.Equating real and imaginary components yield thesolution,

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Slamet is currently working as a researcher at the Reseacrh andDevelopment Center for Electricity, new energy, renewable, and energyconservation, Ministry of Energy and Mineral Resources. Jl. Ciledug RayaKav. 109, Kebayoran Lama - Jakarta Selatan, Indonesia. E-mail:[email protected]

This paper presents an active filter in power invertercontrol method entitled SVPWM strategy based on

m microcontroller atmega 16 [2][3].

International Journal of Scientific & Engineering Research, Volume 4, Issue 3, March-2013 ISSN 2229-5518

IJSER © 2013 http://www.ijser.org

00

1

sin( )3

2sin3

m

V TTsvV

(active time for sv1) (3)

0 02

sin2sin

3m

V TTsvV

(active time for sv2) (4)

Fig. 1. Eight possible switch combinations for a threephase

Fig 2. Space Vector representation

Since1, 20

2TTsv Tsv

, the maximum possible

magnitude for Vo is Vm, which can occur at

03

or . From simple geometry, the limiting

case for the constraint1 2 2

TTsv Tsv occurs at

0 6 which means,

01 22sin

6 1sin

2 3m

VTsv TsvT V

(5)

and this relationship constrains the maximum possiblemagnitude of Vo to,

01sin( )

3 3m busV V V (6)

where Vbus is the D.C link voltage. Since Vo is themagnitude of the output phase voltage, the maximumpossible line to line output voltage using Space VectorPWM must equal,

0( ) 03 *L L busV V V (7)

So duration of time switching or duty cycle for sector1,2...6 can expressed in tables of 1 as follows:

Table 1. Expressions of the duty cycles in eachsector[5]

This result represents that SVPWM is an intrinsically aregular sampled process, since in essence it matchesthe sum of two space vector volt– second averagesover a half carrier period to a sampled target volt–second average [2].

Hardware ImplementationThis section presents the hardware implementation

in the laboratory. There are several steps involved inimplementing the hardware which can be representedin the block diagram shown in Fig.3. Here 5 V DCsupply is given to Atmega 16 µ- controller and theTimer circuit , the output of the µ- controller is fed tointerfacing circuit, than to the opto isolator circuit ,which isolates the high voltage of the inverter circuit(400V dc) from the rest of low voltage TTL and otherlow voltage components. The output of the optoisolator and the interface circuit is fed to the gate ofeach switching device. Each opto isolator is excited byindependent power supply for isolation purpose. Themicrocontroller needs to supply signals to a controllerwhich controls an inductive load such as a motor. BackEMF spikes from an inductive load can easily glitch, or



destroy a microcontroller. Back EMF spikes typicallymanifest themselves as very short duration spikeswhich may or may not contain enough energy toactually destroy a microcontroller. Hence by using theopto coupler such high voltage spikes etc can beprevented[1].

Fig.3. Block Diagram representation of gating signalgeneration.

3 EXPERIMENTAL RESULTSTo prove that signal formed have been sinusoidal,

hence done decrement of form signal pwmA withpwmB causing is obtained form of signal pwmAB likethe one shown to Figure 4, 5, and 6 as follows.

Output of pwm signal at fs = 25 Hertzs

-8

-6

-4

-2

0

2

4

6

8

0 1000 2000 3000 4000 5000

Fig. 3. Pwm Signal_AB at fs=25 HertsOutput of pwm signal at fs = 50 Hertzs

-8

-6

-4

-2

0

2

4

6

8

0 1000 2000 3000 4000 5000

Fig. 4. pwm signal _AB at fs=50 Herts

Output of pwm signal at fs = 100 Hertzs

-8

-6

-4

-2

0

2

4

6

8

0 1000 2000 3000 4000 5000

Fig. 5. pwm signal _AB at fs=100 HertsFrom the result of testing of hadware and software,shown at fig. 3 resulted Ts= 40ms during one priode atsetting point fs=25Hz. For setting point fs=50Hz,obtained Ts=20ms during one priode. While is settingpoint fs=100Hz, obtained Ts=10ms during one periods.So increasingly is boosted up sinusoidal frequency,hence time switching faster. While the inverter need tobe made output voltage wave that is not harmonicbecause the harmonic can result additional heating atmotor so can be made damage to the motor. Thereforespectrum of FFT (fast fourier transform) needed toknows THD ( Total Harmonics Distortion). From theresult of testing, spectrum of FFT shown to fig. 7, 8,and 9 as follows.

Vol

t

10

VAB

30 40

Time (ms)20

Vol

t

10

VAB

30 4020

Time (ms)

h6= 0.1

h2= 0.2

h3= 0.6

h5 = 0.2

h4= 0.1h7= 0.1

h8= 0.1

h6= 0.1

h2= 0.1

h3= 1.2

h5= 0.2

h4= 0.2 h7= 0.1

Vol

t

10

VAB

30 40

Time (ms)20

Fig. 6 Spectrum of FFT at fs = 25Hz

Fig. 7 Spectrum of FFT at fs = 50Hz



Fig. 8. Spectrum FFT at fs = 100Hz

Total Harmonic Distortion THD, reflects energy of thewaveform harmonic content and is defined as equationof 8[11].

%*100[%]1

2

1

h

h

h

VVTHD (8)

Where :Vh : Amplitude harmonic voltageh : Order harmonic

V1 : Amplitude fundamental voltage

THD at measuring of fundamental frequency fs = 25Hz

%51.0

51.0

51.0

52.0

51.0

56.0

52.0*100[%]

2222222

THD

%0192.0*100[%] THD%1385.0*100[%] THD

= 13.85 %THD at measuring of fundamental frequency fs = 50Hz

%51.0

51.0

52.0

52.0

52.1

51.0*100[%]

222222

THD

%062.0*100[%] THD%2489.0*100[%] THD

= 24.89%

THD at measuring of fundamental frequency fs =100Hz

%515.0

515.0

51.0

515.0

51.0

55.0

565.0*100[%]

2222222

THD

%0304.0*100[%] THD%1743.0*100[%] THD

= 17.43 %

5 CONCLUSIONS

Based on the result of design, realization andtesting to generate SVPWM signal, hence inferentialsome things as follows that the Generation of SVPWMsignal with the Space Vector method can be realized tocarrier frequency is about 490Hz appliesmicrocontroller AVR type Atmega16. And with thespace vector PWM method based on microcontrollerAtmega16, value THD which is measurable atsinusoidal frequency of 25Hz, 50Hz, and 100Hz is13.85%, 23.89%, and 17.43%.

6 ACKNOWLEDGMENTS

The authors would like to thank The Reseacrh andDevelopment Center for Electricity, New Energy,Renewable, and Energy Conservation, Ministry ofEnergy and Mineral Resources for their assistance andfinancial support.

REFERENCES

[1] B. Muralidhara, Space Vector PWM SignalGeneration for a Three Phase Inverter and HardwareImplementation Using µ- Controller InternationalJournal of Engineering Science and Technology Vol.2(10), 2010, ISSN 5074-5979

[2] Navpreet Singh Tung, Dynamics of IGBT basedPWM Converter A Case Study, International Journal ofEngineering Science and Technology (IJEST), ISSN :0975-5462, Vol. 4 No.04 April 2012

[3] A. Djerioui, Dpc-Swiching Table control for PWMRectifier With the function of an Active Power FilterBased on a Novel Virtual Flux Observer, InternationalJournal Of Scientific & Engineering Research Volume3, Issue 10, October-2012 , ISSN 2229-5518

[4]. Nalin Kant Mohanty, Microcontroller Based PWMControlled Four Switch Three Phase Inverter FedInduction Motor Drive Vol. 7, No. 2, November 2010,Serbian Journal Of Electrical Engineering, 195-204

h2= 0.65h3= 0.5 h5=

0.15

h4= 0.1

h6= 0.1

h7= 0.15

h8= 0.15



[5]. Bin Wu, “High-Power Converters and AC Drives”,IEEE press, John Wiley & Sons, Inc., Hoboken, NewJersey, 2006.

[6] K. Zhou, D. Wang, “Relation between space-vectormodulation and three-phase carrier-based PWM”,IEEE Transactions on Industrial Electronics, Vol. 49,No. 1, pp 186-196, February 2002.

[7]. Mohd Wazir Bin Mustafa, “Static And DynamicImpacts Of Three To Six-Phase Conversion Of SelectedTransmission Line In An Electric Energy System”,Research vote no:74164, Universiti Teknologi Malaysia,2006.

[8]. Peter Vas, “Electrical Machines and Drives Aspace-vector theory approach”, Oxforf UniversityPress, New York, 1992.

[9] Raman Nair Harish Gopala Pillai, “ Design AndDevelopment Of Embedded Dsp Controllers ForPower Electronic Applications”, Thesis, University OfTexas At Arlington, May 2006.

[10]. Remus Teodorescu, “Space Vector ModulationApplied to Modular Multilevel Converters”,Department of Electrical Engineering,Texas A&MUniversity, 1999.

[11]. Zaenal Salam & Khosru Mohammad Salim,“Generation of Pulse Width Modulation(PWM) Signalfor Three-Phase Inverter Using A Single ChipMicrocontroller”, , Jurnal Teknologi, UniversitiTeknologi Malaysia, 34(D) Jun 2001.



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Generation of Space Vector PWM Using Microcontroller Atmega · PDF fileGeneration of Space Vector PWM Using Microcontroller Atmega 16 ... (SVPWM) signals. The main feature of the research