International Journal of Applied Engineering Research ISSN 0973-4562 Volume 11, Number 6 (2016) pp 4485-4490
© Research India Publications. http://www.ripublication.com
Simulation and Analysis of Conventional and Non-Conventional Three
Phase Five Level Multilevel Current Source Inverters
Mr. Vinesh Kapadia
Research Scholar at - V. T. Patel Department of Electronics and Communication Engineering
Faculty of Technology & Engineering, Charotar University of Science and Technology, Changa, Gujarat, India.
And Head of Department Electronics & Communication Engg. Dept. at S. N. Patel Institute of Technology and Research Centre,
Umrkah, Ta. Bardoli, Dist. Surat, Gujarat, India.
Dr. Hina Chandwani
Associate Professor, Department of Electrical Engineering,
The Maharaja Sayajirao University of Baroda, Vadodara, Gujarat, India
1
Abstract
This paper presents a study and analysisof conventionaland
non-conventional 5-level multilevel current source inverters.
To facilitate for a convergence, the angle control method for
harmonic control has been applied to all the circuits in
accordance with an appropriate switching table. The single
phase circuits are implemented in a MATLAB/SIMULINK
environment, the multilevel current waveform through the
resistive load has been observed (same for all) and the total
harmonic distortion recorded. Based on simulation results a
comparison is proposed at the end comparing the number of
switches, number of inductors required and the total harmonic
distortion resulting that the a particularnon-conventional
topology is more feasible for a three phase actual hardware
implementation.
the switching is done according tothe angle control, this
method is kept the same for all so as to facilitate for a
comparison, the waveforms have been captured and the
percentage total harmonic distortion (%THD) has been
recorded.
Keywords: Cascade H-Bridge, Current Source Inverter (CSI),
Diode-Clamped, Flying Capacitor, Multilevel, Multilevel
Current Source Inverter (MCSI), Total Harmonic Distortion
(THD).
Vo 
The Angle Control Switching Method
Considering here a 5 level Multilevel Inverter, the firing
angles are controlled so as to establish a 5 level current
waveform through the load. By proper selection of the firing
(displacement angles α) angles it is possible to try and
eliminate or say minimize those particular harmonics.
The fourier series for unipolar output voltages per half cycle
can be expressed as (due to symmetry):


n 1,3,5,
Bn sin(nt )
m
4Vs 

k
1

 1 cos  n k  for n=1, 3, 5,..


n  k 1


where 1   2  ....   k 
2
Bn 
Introduction
Most traditionally, voltage source inverters are very common
and in wide use. Though the current source inverter dates back
to earlier than 1988, but was not as widely used as compared
to voltage source inverters (VSI) and multilevel voltage
source inverter (MVSI). Compared to two-level inverters,
multilevel inverters have advantages for higher power
applications, including reduced harmonics and reduced
switching device voltage and current stresses. The CSIs have
some advantages over VSIs such as more stable operating
conditions, direct control of the output current, faster dynamic
response (in some cases) and easier fault management [1-3].
In this paper the conventional and non-conventional three
phase five level MCSI: i) Cascade H-Bridge[4-6], ii) Dual of
Flying Capacitor i. e. Flying Inductor[7], iii) Diode
Clamped[8], iv) Non-Conventional Circuit #1v) NonConventional Circuit #2 and vi) Non-Conventional Circuit #3
[8-12] are simulated in MATLAB-SIMULINK environment,
The third and fifth harmonics would be eliminated if
1  cos31  cos3 2  0
1  cos51  cos5 2  0
(1)
(2)
[13-14] Assuming and initial value of α1 = 0 and calculating
in an iterative manner till the results become stable we get the
values as tabulated in TABLE I;
Table I: Iterations for the Angles
Iterations
α1
α2
Initially assuming α1=0 0
0. 52359
First
0. 28728 0. 64242
Second
0. 31366 0. 66478
Third
0. 31084 0. 66229
Fourth
0. 31127 0. 66268
Fifth
0. 31121 0. 66262
Sixth
0. 31122 0. 66263
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International Journal of Applied Engineering Research ISSN 0973-4562 Volume 11, Number 6 (2016) pp 4485-4490
© Research India Publications. http://www.ripublication.com
The values are radians, hence in degree, α1= 17. 831degree
and α2= 37. 966 degree.
So the other switching instants would be
180-α1 = 162. 17 degree,
180-α2 = 142. 04 degree,
180+α1 = 197. 83 degree,
180+α2 = 217. 96 degree,
360-α1 = 342. 17 degree and
360-α2 = 322. 04 degree
These values in degree would be converted then in to time (for
50Hz system). This results into one cycle being divided into
13slots the resulting waveform is shown below:
Figure 1: Resultant 5level currentwaveform (only a single
phase is shown for above calculated firing timings)
Simulation of Conventional Mcsi Circuits
Figure 2 is circuit diagram of a 5 Level MCSI using cascade
H-bridge topology. The TABLE II covers not only the
switching states but also the parameters required to be set in
the pulse generators (not shown) for MATLAB-SIMULINK
simulation. The period to be set is 0. 02 second in all the pulse
generators.
Figure 3 show the load current waveform and Figure 4 the
corresponding Total Harmonic Distortion (THD). The current
value of each of the current source is 5A resulting in a total
current through the load as 10A
Using similar techniques, the simulation has been carried out
for a 5 level Flying Inductor (dual of flying capacitor with
reference to VSI) (Fig. 5) and a 5 level Diode Clamped
Multilevel Inverter (Fig 8). The single phase current
waveform and the corresponding THD are recorded and later
tabulated
Figure 2. A 5 level MCSI in Cascade H-Bridge Configuration
(only a single phase is shown)
Table II. Switching scheme and pulse generator settings for
the 5 level MCSI Cascade H-Bridge Configuration
(Fig. 2 & Fig. 3)
Figure 3. The resultant 5level currentwaveform of the 5 level
MCSI in Cascade H-Bridge configuration (single phase)
Pulse
Switches
to
be Delay in % of period
Generator connected to the second to be kept
pulse generator
on
PG1
S11, S12, S21, S22
0
4. 995
PG2
S11, S14
0. 000991 40. 09
PGA
S21, S22
0. 000991 5. 59
PG3
S21, S24
0. 002109 28. 91
PG4
S13, S14, S23, S24
0. 009009 9. 91
PG5
S13, S12
0. 010991 40. 09
PGB
S23, S24
0. 010991 5. 59
PG6
S23, S22
0. 012109 28. 91
Figure 4: THD spectrum of Figure 3
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International Journal of Applied Engineering Research ISSN 0973-4562 Volume 11, Number 6 (2016) pp 4485-4490
© Research India Publications. http://www.ripublication.com
Figure 7. THD spectrum of Figure 6
Figure8. A5 level MCSI in Diode Clamped Configuration
(only a single phase is shown, current source value 10A)
Figure 5: A 5 level MCSI in Flying Inductor Configuration
(only a single phase is shown, current source value 10A)
Figure 9. Theresultant5 level current waveform of the 5 level
MCSI in Diode Clamped Configuration (single phase)
Figure 6. The resultant 5 level current waveform of the 5
level MCSI in Flying Inductor Configuration (single phase)
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International Journal of Applied Engineering Research ISSN 0973-4562 Volume 11, Number 6 (2016) pp 4485-4490
© Research India Publications. http://www.ripublication.com
Figure 12. The resultant5 level current waveform of the 5
level MCSI in Non-Conventional #1 Configuration (single
phase)
Figure 10. THD spectrum of Figure 9
These three circuits form the conventional multilevel inverters
(5 levels in this case).
Simulationof Non-Conventional Circuits
Followinga method similar to the one described above, three
non-conventional circuits were simulated, the waveforms
observed and the THD recorded (current source value is taken
as 10A for all). Figure 10, shows the three phase current
waveform through the load. Only one Figure of current
waveform is shown as all the conventional and nonconventional current waveforms are the same.
Figure 13. THD spectrum of Figure12
Figure 14. 5 level MCSI Non-Conventional #2 Configuration
(only single phase is shown).
Figure11. 5 level MCSI Non-Conventional #1 Configuration
(only single phase is shown).
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International Journal of Applied Engineering Research ISSN 0973-4562 Volume 11, Number 6 (2016) pp 4485-4490
© Research India Publications. http://www.ripublication.com
Figure 15. The resultant5 level current waveform of the 5
level MCSI in Non-Conventional #2 Configuration (single
phase)
Figure 18. 5 levelMCSI 3 phaseLine Current Waveform
through the load
Figure 16. THD spectrum of Figure15
Figure 19. THD spectrum of Figure18.
These three circuits form the non-conventional multilevel
inverters (for 5 levels in this case). It is to be noted that the
circuit shown in Figure 17 can be used for 3 phase purposes
only whereas all the other circuits may be used for single
phase and hence the single phase circuitsmay be used modular
wise for 3 phase implementations
Conclusion
A comparison of the six circuits (consideringthree
phaseconfigurations) on the basis of number inductors (it is to
be noted that the current source itself is made of a DC voltage
source with a series inductor, this inductor is also accounted
for in the table below), the number of switches and on the
percentage (%)THD is tabulated in TABLE III
It may be concluded that for a 5 level MCSI keeping
switching topology the same for all the six circuits, the %
THD is more or less similar for all and dynamic variations is
Figure 17. 5 level MCSI Non-Conventional #3Configuration
(three phase)
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International Journal of Applied Engineering Research ISSN 0973-4562 Volume 11, Number 6 (2016) pp 4485-4490
© Research India Publications. http://www.ripublication.com
from 17. 99 to18. 68 = 0. 69 only. Non-Conventional Circuit
#2 is having the least % THD i. e. 17. 99, however for actual
implementation 4 inductors and 18 switches would be
required resulting in more cost and complexity. The NonConventional Circuit #3 is having %THD of 18. 68 and the
number of inductors and switches required are 3 and 12
respectively (least out of all in both the cases) for actual
implementation hence it may be chosen for a particular
application or an actual implementation.
[6]
[7]
Table III. Comparison of the 3 phase 5 level MCSI circuits
on basis of number of inductors, switches & % THD
[8]
3 Phase Power No.
Circuit
Inductors
Cascade H-Bridge 6
Flying Inductor
19
Diode Clamped
19
Non-Conventional 7
#1
Non-Conventional 4
#2
Non-Conventional 3
#3
of No.
Switches
24
24
24
12
of %THD
18. 30
18. 19
18. 18
18. 18
18
17. 99
12
18. 68
[9]
[10]
References
[1]
[2]
[3]
[4]
[5]
[11]
BaoJian-yu, BaoWei-bing and Zhong-chao Zhang,
2010, “Generalized multilevel current source inverter
topology with self-balancing current”, Journal of
Zhejiang University-SCIENCE C (Computers &
Electronics), ISSN 1869-1951 (Print); ISSN 1869196X (Online), pp. 555-561.
B. K. Bose, 2009, “Power electronics and motor
drives recent progress and perspective, ” IEEE Trans.
Ind. Elecrtron., Vol. 56, No. 2, pp. 581–588.
Vinesh Kapadia and Dr. HinaChandwani, 2012, "
Modeling of Current Source Inverter from Voltage
Source Inverter Based on Duality Concept"
International Journal of Engineering Research and
Development e-ISSN: 2278-067X, p-ISSN: 2278800X, www. ijerd. com Volume 4, Issue 1, pp. 1722.
Vinesh Kapadia and Dr. HinaChandwani, 2012, " A
Review On Current Source Inverter Fed Ac Drives
And Multilevel Current Source Inverters: Part -1:
CSI Fed Ac Drives", International Journal Of
Electrical Engineering & Technology (IJEET) ISSN
0976 – 6545 (Print) ISSN 0976 – 6553 (Online)
Volume 3, Issue 3, pp. 80-88
Vinesh Kapadia and Dr. HinaChandwani, 2012, " A
Review On Current Source Inverter Fed Ac Drives
and Multilevel Current Source Inverters: Part -2:
Multilevel CSIs". International Journal Of Electrical
Engineering & Technology (IJEET) ISSN 0976 –
6545 (Print) ISSN 0976 – 6553 (Online) Volume 3,
Issue 3, pp. 102-109.
[12]
[13]
[14]
4490
Vinesh Kapadia and Dr. HinaChandwani, 2013,
“Comparison Of Modulation Techniques For
Cascaded H-Bridge Type Multilevel Current Source
Inverter” International Journal Of Advanced
Research in Engineering And Technology (IJAERT)
ISSN: 0976 - 6480 (Print) ISSN: 0976 - 6499
(Online) Volume 4, Issue 2, pp. 181-190.
ZhiHong Bai and Zhong Chao Zhang, 2008,
“Conformation of Multilevel Current Source
Converter Topologies Using the Duality Principle”
IEEE Transactions On Power Electronics, Vol. 23,
No. 5, pp. 2260-2267.
Jian-yuBao, WeibingBao, Siran Wang and
Zhongchao Zhang, 2010, “Multilevel current source
inverter topologies based on the duality principle”,
IEEE Applied Power Electronics Conference and
Exposition (APEC), pp. 1097 – 1100.
Zhi-hong Bai, Zhongchao Zhang and Yao Zhang,
2007, "A Generalized Three-Phase Multilevel
Current Source Inverter with Carrier Phase-Shifted
SPWM", Power Electronics Specialists Conference,
IEEE, ISSN: 0275-9306, E-ISBN : 978-1-42440655-5, Print ISBN: 978-1-4244-0654-8, pp. 201552060.
Jian-yuBao, Zhi-hong Bai, Wang Qing-song, and
Zhang Zhong-chao, 2006, “A New Three-Phase 5Level Current-Source Inverter”, Journal of Zhejiang
University SCIENCE A ISSN 1009-3095 (Print);
ISSN 1862-1775 (Online), pp. 1973-1978
M. E. Ahmed, S. Mekhilef, 2009, “Design and
implementation of a multi-level three-phase inverter
with less switches and low output voltage distortion,
” Journal of Power Electronics, Vol. 9, No. 4, pp.
593–603.
Nimrod Vázquez, Hector López, Claudia Hernández,
Eslí Vázquez, René Osorio, and Jaime Arau, 2010,
“A Different Multilevel Current-Source Inverter”,
IEEE Transactions On Industrial Electronics, Vol.
57, No. 8, August 2010, pp. 2623-2632.
Jagdish Kumar, Biswarup Das, and Pramod Agarwal,
2008, “Selective Harmonic Elimination Technique
for a Multilevel Inverter”, Fifteenth National Power
Systems Conference (NPSC), IIT Bombay.
A. Shoulaei, M. Asadi, D. Habibinia and H. Feshki,
2007, “A Novel Method for Optimal Design of Input
Inductor in Current Source Inverters with SHEM
Switching Method”, First International Power
Engineering and Optimization Conference (PEOCO),
pp. 142.