Indian J.Sci.Res. 7 (1): 275-281, 2014
ISSN: 0976-2876 (Print)
ISSN: 2250-0138(Online)
COMPARISON OF GRID CONNECT MULTI-LEVEL INVERTER
MILAD TEYMOORIYANa1AND MAHDI SALIMIb
ab
Department of Engineering, Ardabil Branch, Islamic Azad University, Ardabil, Iran
ABSTRACT
In this paper, multilevel inverters structures are compared. These converters consist of series H-bridge inverter,
diode clamping and floating capacitors. The study also investigates the advantages and disadvantages of the different
topologies. Finally, the structures which can be used in combination with multi-level inverter connected to the grid have been
developed.
KEYWORDS: Multi-Level Inverter
In recent years, new industrial applications for
medium and high voltage motors (which may require
voltages in megawatts ranges) applied these inverters
which can be used as an alternative to the power of a
multilevel converter for high and medium renewable
energy sources . The use of multilevel converters has been
started since 1975 [1], which is in fact the development of
the two-level converters. Purpose of the use of multilevel
converters, access to a high power is the key to a series of
semiconductor strength and low DC voltage sources for
energy conversion based on elements such as capacitors,
batteries and renewable energy sources is implemented.
Using the appropriate switching and considering several
sources of input DC converters, high voltage can be
obtained in a multilevel converter output. Multilevel
converters have advantages and disadvantages compared
to two level converters considering switching frequency
and Pulse Width Modulation (PWM) can include.
1 - To be expensive due to the high number of switching
elements (which cannot be economically affordable.)
2 - Design complexity due to the lack of sufficient
knowledge (creates problems)
1- Quality of the AC output waveform: a multilevel
converter cannot only produce a voltage output with
extremely low distortion, also capable of decreased stress
dv /dt. So the problem of electromagnetic interference
(EMI) can be reduced.
Transformers series H: Structure of the converter in
Figure 1 is shown.
2 - Less Common Mode voltage (CM): less CM voltage
multilevel converters and therefore less stress on the
motor bearings as well as semiconductor components
connected to a multi-level inverter will be reduced. [2]
3 - The input source: the use of multilevel converters can
already having low distortion input sources, problems
related to power quality in distribution systems to
overcome.
4 - Switching frequency: multilevel converters can be
both primary and high switching frequency to be used.
Lower switching frequency usually means higher
efficiency as well.
The disadvantages of multilevel converters can
also be summarized as follows:
1
Corresponding author
3 - Different techniques for controlling converters,
multilevel provided. Example can be pulse width
modulation sine, eliminating the harmonic selective
modulation vector space mentioned. Most important
applications of inverters multilevel can to drive motors,
medium voltage, transmission systems AC flexible and
renewable energy sources are connected to the grid [4, 3].
In this section, the advantages and disadvantages of
multilevel converters, kind of actives switch usage, how
to charge and discharge the closing of diodes and
capacitors of the converter structure and especially for the
inverter connected to the grid will be reviewed.
PREPARE YOUR PAPER BEFORE STYLING
Figure 1: Structure of a single-phase H-bridge
converter
TEYMOORIYAN AND SALIMI: COMPARISON OF GRID CONNECT MULTI-LEVEL INVERTER
H-bridge converters successively by each of the
three levels voltage [-Vdc 0 Vdc+ ] won with a separate
DC sources in Figure 1 is shown. Using multilevel
converters are can the state inverter, rectification,
charging and braking could be.
How to remove harmonics of the fifth, seventh,
eleventh and thirteenth on a suitable switching lowfrequency figure (2) is shown in [5].
Figure 2: Eleven level H-bridge converte with five
separate DC source
disadvantages of the H-bridge multilevel inverter are as
follows:
Advantages: 1 - number of output voltage levels more
than twice the number of DC input sources
(M = 2m +1) in this regard:
M: number of output levels
m: number of H-bridge used in each phase
2 - There is packet-like modules.
3 - Design of control system is very simple.
Disadvantages: 1- separate DC sources required for each
H-bridge
Diode clamped multilevel inverter
Structure of such a converter in Figure 4 is given
in [6].
Figure 4: Structure of three-phase inverter based on
diode-clamped
In Figure 3 the application of multi-level inverter
for electric vehicles is presented.
Figure 3: Multi-level three-phase inverter based on
sequential H-bridge to drive the electric motor with
the batteries located in the DC Converter
Inverter shown in Figure (4) instead of the threelevel output voltage level output for multiple uses.
For example, in Figure 4, six-level inverter
output voltage is used and the principles in Table 1 and
Figure (5) are given.
The circuit shown in Figure (3) is able to drive
the electric motor and batteries located in the dynamic
braking of DC side of the inverter used. Advantages and
Indian J.Sci.Res. 7 (1): 275-281, 2014
TEYMOORIYAN AND SALIMI: COMPARISON OF GRID CONNECT MULTI-LEVEL INVERTER
Table 1: Diode clamped inverter and switches voltage
level corresponding to six different
Advantages and disadvantages
converter is discussed in [8.7].
of such
a
Advantages:
1.
All phases of the DC capacitors are identical, so the
fewer the number of capacitors required.
2.
Ability to charge the capacitors of the group is
allowed.
3.
The switching frequency of the main component, the
converter efficiency is high.
Disadvantages:
Figure 5: The voltage waveform of the inverter linelevel diode clamped six
1.
Ability to pass the real power of the system is very
difficult because the capacitor charging or
discharging Add to Medieval tend voltage may be
unbalanced.
2.
The number of clamping diodes required levels is
related to the square of the number of diodes can
increase exponentially.
Floating capacitor based multilevel inverter [9]:
Figure 6: Structure of three-phase inverter six levels based on the floating capacitor
Figure (6) shows, instead of clamping diodes are
used in a manner different from that usedCapacitors to
Indian J.Sci.Res. 7 (1): 275-281, 2014
increase voltage output waveform and There is no
resemblance between the diode and clamps' .
TEYMOORIYAN AND SALIMI: COMPARISON OF GRID CONNECT MULTI-LEVEL INVERTER
Table 2: Usage-based inverter is shown floating capacitors [11, 10].
The advantages and disadvantages of using a
converter based on the floating capacitors can be
summarized as follows:
Figure 7: P2 generalized multilevel topology for a
multilevel inverter
Advantages:
1.
Adding capacitors to balance the voltage levels are
available.
2.
Active and reactive power flow can be maintained
easily.
Disadvantages:
1.
Complex control voltage due to variations in their
numbers.
2.
Before charging capacitors, circuit startup are
associated with problems .
3.
The large number of capacitors increases the
complexity of life, cost, and size.
Combination of structures
1 - Floating capacitance diode clamped multilevel inverter
can be combined with a new structure obtained in the
form (7) is shown.
Indian J.Sci.Res. 7 (1): 275-281, 2014
The multilevel topology can balance each
voltage level to produce. Two-level converters can also be
achieved with this topology [12]
2 - Hybrid multilevel converters: To reduce the
number of independent sources in a DC high voltage
applications can be structured as shown in Figure (8) can
be used [13]. The main drawback to this method is the
complexity of its design.
TEYMOORIYAN AND SALIMI: COMPARISON OF GRID CONNECT MULTI-LEVEL INVERTER
Figure 8: A hybrid multilevel inverter using three-level
diode-clamped H-bridge structure is used as the
primary cells [15.14].
inverters is in inverter mode and another is in rectification
work. Such an arrangement is well suited to drive high
power electric motors.
Figure 10: Structure of the diode clamped converter
with six consecutive
3- Multilevel inverter switching software: a multilevel
converter in this case in order to avoid switching losses
and increase efficiency are used.
Figure 9: Diode clamped inverter with soft switching
in
CONCLUSION
In this paper, a multilevel inverter consists of
1 - H -bridge inverter based multilevel successive, 2 H -bridge inverter based on multi-level squence of charge
and discharge capabilities by batteries located in the DC
inverter, 3 - Phase six diode clamped inverter with, 4 three-phase inverter based on six levels floating capacitor
,5 - P2 generalized topology multi-level multilevel
inverter to convert the power output of, 6 - Hybrid
multilevel inverter, 7 - Diode clamped inverter with soft
switching in, 8 - six- level inverter converts the
comparison. These comparisons include the advantages
and disadvantages of each of them be.
In Table (3 ), the comparison of different
multilevel inverters in presented.
4- Converters with diode clamped back to back: Use
the same inverter converters with diode clamped in the
form (10) is shown [17.16]. In this structure, one of the
Table 3: Comparison of multilevel inverter
Inverters
Indian J.Sci.Res. 7 (1): 275-281, 2014
Advantages
Disadvantages
TEYMOORIYAN AND SALIMI: COMPARISON OF GRID CONNECT MULTI-LEVEL INVERTER
Consecutive H-bridge
inverter
1-number of output voltage levels more than two
times the number of sources
2 - Ability Classification System Modules are like.
3 - Design of control system is very simple.
Needed to separate H-bridge DC
Sources
Diode clamped
multilevel inverter with
Using the same DC
1 - Keying phase capacitors
That are why many smaller capacitors are required
2 - the possibility of charging the capacitor as a
whole is possible.
3 - The switching frequency of the main component,
the converter efficiency is high.
1- Ability to pass the real power of the
system is very difficult because they
tend to charge and discharge the
capacitors tend to add.
2 - The number of clamping diodes
lining increases exponentially with the
square of the number of connections
they are needed.
Floating capacitor
multilevel inverter based
1- Add capacitor voltage balancing is available.
2 -Active and reactive power flow can be controlled
3 - Using a large number of input capacitors enables
the elimination of the long output inverter can
provide.
1- Complete control voltage due to the
multiplicity of their
2 - Before charging capacitors, circuit
startup problems associated.
3 - Number of capacitors complicated,
more expensive and has more volume.
REFERENCES
R. H. Baker and L. H. Bannister, “Electric Power
Converter,”U.S.Patent 3 867 643, Feb. 1975.
E. Cengelci, S. U. Sulistijo, B. O. Woom, P. Enjeti, R.
Teodorescu, and F. Blaabjerg, “A New Medium
Voltage PWM Inverter Topology for Adjustable
Speed Drives,” in Conf. Rec. IEEE-IAS Annu.
Meeting, St. Louis, MO, Oct. 1998, pp. 1416–14
L. M. Tolbert, F. Z. Peng, and T. G. Habetler, “A
Multilevel Converter-based Universal Power
Conditioner,”IEEE Transactions on Industry
Applications, vol. 36, no. 2, Mar./Apr. 2000, pp.
596–603.
L. M. Tolbert, F. Z. Peng, and T. G. Habetler, “Multilevel
Inverters
for
Electric
Vehicle
Applications,”IEEE Workshop on Power
Electronics in Transportation, Oct. 22–23 1998,
Dearborn, Michigan, pp. 1424–1431.
R. W. Menzies and Y. Zhuang, “Advanced Static
Compensation Using a Multilevel GTO
ThyristorInverter,”IEEE Transactions on Power
Delivery, vol. 10, no. 2, Apr. 1995, pp. 732–738.
A. Nabae, I. Takahashi, and H. Akagi, “A New Neutralpoint
Clamped
PWM
Inverter,”IEEE
Transactions on Industry Applications, vol. IA17, Sept./Oct. 1981, pp. 518–523.
C. Hochgraf, R. Lasseter, D. Divan, and T. A. Lipo,
“Comparison of Multilevel Inverters for Static
Indian J.Sci.Res. 7 (1): 275-281, 2014
VarCompensation,”Conference Record – IEEE
Industry Applications Society 29th Annual
Meeting, 1994, pp. 921–928.
J. S. Lai and F. Z. Peng, “Multilevel Converters – A New
Breed of Power Converters,”IEEE Transactions
on Industry Applications, vol. 32, no. 3, May
1996, pp. 509–517.
T. A. Meynard and H. Foch, “Multi-Level Conversion:
High Voltage Choppers and Voltage-Source
Inverters,”IEEE Power Electronics Specialists
Conference, 1992, pp. 397–403.
J. S. Lai and F. Z. Peng, “Multilevel Converters – A New
Breed of Power Converters,”IEEE Transactions
on Industry Applications,vol. 32, May/June
1996, pp. 509–517.
L. M. Tolbert, F. Z. Peng, and T. Habetler, “Multilevel
Converters for Large Electric drives,”IEEE
Transactions on Industry Applications, vol. 35,
Jan./Feb. 1999, pp. 36–44.
F. Z. Peng, “A Generalized Multilevel Converter
Topology with Self Voltage Balancing,”IEEE
Transactions on Industry Applications, vol. 37,
Mar./Apr. 2001, pp. 611–618.
W. A. Hill and C. D. Harbourt, “Performance of Medium
Voltage Multilevel Converters,” in Conf. Rec.
IEEE-IAS Annu. Meeting, Oct. 1999, Phoenix,
AZ, pp. 1186–1192.
TEYMOORIYAN AND SALIMI: COMPARISON OF GRID CONNECT MULTI-LEVEL INVERTER
J. Rodriguez, J. S. Lai, and F. Z. Peng, “Multilevel
Inverters: Survey of Topologies, Controls, and
Applications,”IEEE Transactions on Industry
Applications, vol. 49, no. 4, Aug. 2002, pp. 724–
738.
B. M. Song and J. S. Lai, “A Multilevel Soft-switching
Inverter
with
Inductor
Coupling,”IEEE
Transactions on Industry. Applications, vol. 37,
Mar./Apr. 2001, pp. 628–636.
Indian J.Sci.Res. 7 (1): 275-281, 2014
A. van Zyl, J. H. R. Enslin, and R. Spee, “A New Unified
Approach to Power Quality Management,”IEEE
Transactions on Power Electronics, vol. 11, no.
5, Sept. 1996, pp. 691–697.
H. Fujita and H. Akagi, “The Unified Power Quality
Conditioner: The Integration of Series- and
Shunt-Active Filters,”IEEE Transactions on
Power Electronics, vol. 13, no. 2, March 1998,
pp. 315–32.