ISSN (Print) : 2320 – 3765

ISSN (Online): 2278 – 8875

International Journal of Advanced Research in Electrical,

Electronics and Instrumentation Engineering
(An ISO 3297: 2007 Certified Organization)

Vol. 5, Issue 9, September 2016

A Review on Modern Pulse Width Modulation

Techniques Based Inverters
Manish Sahajwani1, Sushma Patel 2
HOD, Dept. of EX, IES IPS Academy Indore (M.P.) India1
M.E. Scholar (Power Electronics), Dept. of EX, IES IPS Academy Indore (M.P.) India2

ABSTRACT: The modern inverter technology for serving the society through comfort, making not only changes the
domestic life style but in industries where VFD and other lifting & tackles require a new and efficient technology for
betterment of performance of the drive and lifting tackles. Here the paper gives the schematic work of various scholars
and comparison of different techniques of different pulse width modulation techniques for Power Electronics Inverters
used for different industrial and commercial applications.
This paper presents few approaches of above, their brief introduction and literature review.

KEYWORDS: PWM, SPWM, SVPWM, Firing Pulse,Inverter

I.INTRODUCTION

Earlier the utilization of electrical energy was simple and straight forward; generation of electricity & its consumption
was a linear process, but now a day’s electrical power system is one of the complex networks in the world with the
invention of new techniques of power control and equipment which have better energy efficiency and efficient control
with fast and smart switching [1, 2]. Since the development of semiconductor devices in the decades of the 1950s the
use of ithas been increased not only in the field of electronics or communication engineering but electrical engineering
too. In Earlier days the switching of electric power for the operation of electrical equipments was either through manual
or through electromechanical switches, but due to fast speed, accuracy and high range the power electronics and solid
state controllers and converters have been used worldwide and in the last two decades their use increases very
rapidly[3].
The inversion process of converting DC into AC has taken place for many applications such as renewable energy
technology, HVDC transmission, Adjustable speeddrives[4] and high frequency industrial heating processes. The
applications using variable frequency inverters are increasing day by day due to its user friendly approach for common
men while the technology behind this is very advanced.
The aim of this paper is to review, classify and illustrate the pulse width modulation techniques. Here is a comparison
among Cycloconverter, LCI and PWM supply is given in the table shows that how the technology has advantages over
other two[2, 5] for different uses in electrical engineering systems pulse width modulation techniques have proven
superiority over other techniques

Table 1
Comparison between different technologies for inverters
Sr. No. Control Feature Cyclo-converter LCI PWM
1 Speed (in Drive) Limited Wide Wide
2 Dynamic response Excellent Good Excellent
3 Torque pulsation Low High Very Low
4 Stability,Good Good Moderate Very good
5 Volumetricpower Moderate Good Very good
density

Copyright to IJAREEIE DOI:10.15662/IJAREEIE.2016.0509011 7233

 ISSN (Print) : 2320 – 3765
ISSN (Online): 2278 – 8875

International Journal of Advanced Research in Electrical,

Electronics and Instrumentation Engineering
(An ISO 3297: 2007 Certified Organization)

Vol. 5, Issue 9, September 2016

II. PULSE WIDTH MODULATION TECHNIQUES AND COMPARISON

Different approaches and classification of PWM techniques has been shown in fig. 1 [4,7]:

Figure 1 Classification of PWM Technique

The figure shows a detailed classification of PWM strategies for different application using unique strategies as per
requirement of supply and end user profile
Among all these techniques here few among them are going to discuss as follows:
A. Pulse Width Modulation
B. Sinusoidal Pulse Width Modulation
C. Space Vector Pulse Width Modulation

A.Pulse Width Modulation

Pulse width modulation is the method of choice to control modern power electronics circuits. The basic idea is to
control the duty cycle of a switch such that a load sees a controllable average voltage[6]. To achieve this, the switching
frequency or repetition frequency of the PWM signal is chosen high enough that the load cannot follow the individual
switching events. Switching, rather than linear operation of the power semiconductors, is of course done to maximize
the efficiency because the power dissipation in a switch is ideally zero in both states. In a typical case, the switching
events are just a blur to the load, which reacts only to the average state of the switch.There are a number of different
methods to generate periodic rectangular waveforms with a varying dutycycle[5, 7] A standard method is the so called
carrier-based PWM technique, which compares a control signalwith a triangle (or sawtooth shaped) waveform. . By
comparing this signal with a reference level, which can vary between 0 and 1 V, a PWM signal with a duty cycle
between 0 and 100% is generated. Because ofthe triangular carrier, the relation between the reference level and the
resulting duty cycle is linear. This method works very well for duty cycles in the range from 5% up to 95% However, if
the reference signal exceeds 100% or falls below 0%, the resulting PWM signal would be always on or alwaysoff,
respectively. This is called overmodulation. This regime must be avoided by proper conditioning ofthe control signal.
In addition, for control signals resulting in PWM signals with duty cycle values ashigh as 99% or as low as 1%, the

Copyright to IJAREEIE DOI:10.15662/IJAREEIE.2016.0509011 7234

 ISSN (Print) : 2320 – 3765
ISSN (Online): 2278 – 8875

International Journal of Advanced Research in Electrical,

Electronics and Instrumentation Engineering
(An ISO 3297: 2007 Certified Organization)

Vol. 5, Issue 9, September 2016

switch may never fully reach the opposite state and spend an undueamount of time in transitions. Therefore, it is
typically recommended to limit the control signal to arange, which avoids overmodulation as well as extremely narrow
pulses. The Duty Cycle is[4,8]:

ActualDurationofPulseinHalfCycle
D ……………(1)
DurationofOneHalfCycle
Therefore rootmean square value of AC output voltage will be
V  DV1 ………………………. (2)

The reader should be reminded that, due to the switching speed of modern power semiconductors, the carrier frequency
can be chosen sufficiently high that the harmonics can be easily filtered with capacitors and inductors of small size

B. Sinusoidal Pulse Width Modulation

In addition to a DC reference signal, any other waveform could be used as the modulation signal as long as the highest
frequency of its AC components are at least an order of magnitude less than the frequency of the carrier signal. To
generate a sinusoidal output voltage for an inverter, which is often desired, the carrier can be modulated with a
sinusoidal reference signal. The ratio between the carrier frequency and the frequency of the modulation signal is lower
than recommended for actual implementation[5,6]. The resulting sinusoidal PWM voltage drives one phase lag of an
inverter. If the voltage level is 1, the upper switch is on, and vice versa. After filtering out the switching frequency
components, the resulting output voltage has the shape and frequency of the modulation signal. For the remaining
phase legs, the same technique, with reference signals that are phase shifted by 120 and 240 degrees, is used. The
amplitude of the output voltage can be controlled by varying the ratio between the peak of the modulation signal and
the peak of the carrier wave. If the amplitude of the modulation signal exceeds the amplitude of the carrier,
overmodulation occurs and the shape of the fundamental of the output voltage deviates from the modulation signal.
Earlier, because the difference between the switching frequency and the fundamental is much larger. Therefore, the
carrier frequency components can be easily removed with LC filters of small size [5,8,15]. In addition, the amplitude of
the output voltage can be controlled simply by varying the amplitude ratio between the modulation signal and the
carrier. If six-step modulation is used, the DC bus voltage would have to be controlled in order to control the amplitude
of the output voltage[2,9].

C. Space Vector Pulse Width Modulation

The Space Vector Pulse Width Modulation is a fast, advanced and efficient Pulse width modulation technique among
all others for VSI fed loads with superiority of good DC utilization voltage and less harmonic problems as compared to
other techniques[8,9]. It has special on off switching sequence of the upper three power devices of a three-phase
voltage source inverters applied for 3phase loads.It is a more soft technique for generating sine wave that provides a
higher voltage to the load side with lower total harmonic distortion. Space Vector Pulse Width Modulation is better to
use as a whole for switching frequency rather than choosing separate modulator for each phase. As the Space Vector
Pulse Width Modulation is more complicated than SPWM than to its easy to use with moderrn DSP based control
circuits for emerging applications[7,9].

We my understand the concept of Space Vector Pulse Width Modulation by considering three phase waves with phase
displacement 120 degree and voltage levels Vr,Vy, Vb as follows[8,10]
VR  Vm Sint

VY  Vm Sin t  120 0  ……….…. (3)
VB  Vm Sint  120 0

These three vectors may represent by single one space vector

Copyright to IJAREEIE DOI:10.15662/IJAREEIE.2016.0509011 7235

 ISSN (Print) : 2320 – 3765
ISSN (Online): 2278 – 8875

International Journal of Advanced Research in Electrical,

Electronics and Instrumentation Engineering
(An ISO 3297: 2007 Certified Organization)

Vol. 5, Issue 9, September 2016

3
VS  Vm Sint  jCost  ……………………. (4)
2
Vs rotates with speed  rad/Sec as represented in fig. 2

Figure 2

Consider a conventional 3 phase bridge VSI which has six switches, three upper and three lower; total 6 switches hence
there are 8 possible combinations (0,0,0), (0,0,1),(0,1,0), (0,1,1), (1,0,0), (1,0,1),(1,1,0),(1,1,1) as shown in the table the
different switching strategies for inverter[1,9,11,12]

Table 2 Different Switching Strategis

State On Device Vrn Vyn Vbn Space Voltage

Vector
0 S4S6S2 0 0 0 (0,0,0)
1 S1S6S2 2Vd/3 -Vd/3 -Vd/3 (1,0,0)
2 S1S3S2 Vd/3 Vd/3 -2Vd/3 (1,1,0)
3 S4S3S2 (0,1,0)
4 S4S3S5 (0,1,1)
5 S4S6S5 (0,0,1)
6 S1S6S5 (1,0,1)
7 S1S3S5 0 0 0 (1,1,1)

From above 8 states 6 states are active while 2 states (0,0,0) and (1,1,1) are short circuited due to switching. The figure
shows the Space vector trajectory and adjustment:

Copyright to IJAREEIE DOI:10.15662/IJAREEIE.2016.0509011 7236

 ISSN (Print) : 2320 – 3765
ISSN (Online): 2278 – 8875

International Journal of Advanced Research in Electrical,

Electronics and Instrumentation Engineering
(An ISO 3297: 2007 Certified Organization)

Vol. 5, Issue 9, September 2016

Figure 3

The total harmonic distortion in space vector pulse width modulation based inverter is the ratio of the root mean square
of the harmonic content to the root mean square value of the fundamental quantity, expressed as a percentage of the
fundamental When the value of current have a harmonic[13,14]

 2
THD   I
k krms
/ I rms *100 …. …….……(5)

III. CONCLUSION

This paper present review of the recent development in the area of PWM. Emphasis has been given to categorizing
various PWM techniques which are reported in the literature. The paper also presented a salient feature of the various
PWM. This paper will serve as a valuable resource to any future worker in this important area of research.In the view
about further work based on this attempt has been going to implement through carrier based frequency & Pulse width
modulation for the efficient control of induction motor drive and other allied activities. Change in modulation index
fundamental frequency may get analyzed.

REFRENCES

[1] Bimal K. Bose, "Modern Power Electronics and AC Drives", Pearson Education, 2003.
[2] Muhammad H. Rashid, "Power Electronics, Circuits, Derives and applications”. Pearson Education Inc. 2004.
[3] Vas, P., “Electrical Machines and Drives a Space-Vector Theory Approach,” Oxford University Press, 1992.
[4] C.M. Poddar,Power Electronics Devices and Circuits,Jain Publication, 1999, 1e
[5] Joseph Vithyathil, Power Electronics , McGraw Hill Publication, 2010
[6] Keith H. Sueker, Power Electronics Design: A Practitioner’s Guide, Newnes Pub, 2005, 1e
[6] S.Prashanth, M.Santhosh, I. Rahul, Space Vector Modulation Algorithm for Multi Level Inverter, International Journal of Scientific &
Engineering Research, Volume 4, Issue 6, June-2013, Pages 1980-1988
[7]Nikola Celanovic, Space Vector Modulation and Control of Multilevel Converter, Ph D Thesis,Virginia Polytechnic Institute, September 20,
2000
[8] A. Cataliotti, F. Genduso, G. RiccoGalluzzo ,A Space Vector Modulation Control Algorithm for VSI Multilevel Converters
[9] M. Nigam, A.Dubey, Design and Implementation of SVPWM Inverter are using Soft Computing, International Journal of Engineering Research
& Technology Vol. 1 Issue 7, Sep. 2012
[10] Nabe, A., Takahashi, I., and Akagi, H., A new neutral-point clamped PWM inverter, IEEE Trans.Ind. Appl.17, 518, 1981.
[11] D. Sasi1, J. Kuruvilla P, Modelling and Simulation of SVPWM Inverter Fed Permanant Magnet Brushless DC Motor Drive, International
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[12]www.mathwork.com (accessed on 19.7.2015)
[13]www.ieeeexplorer.com (accessed on 22.3.2016)
[14] www.elesewhwere.com (accessed on 26.11.2015)

Copyright to IJAREEIE DOI:10.15662/IJAREEIE.2016.0509011 7237