A micro grid is a hybrid power system consists of several distributed resources and local loads .Now a days with increasing on a day to day life micro grid plays a vital role in power generation using Renewable Energy Sources. Usage of power electronic devices in a micro grid results in harmonic generation and leads to various power quality issues. Inorder to overcome voltage fluctuations and over current a magnetic flux control based variable reactor is proposed. The performance of IPQC can be verified by using MATLAB/SIMULINK`

1. 39 International Journal for Modern Trends in Science and Technology
Power Quality Improvement with Multilevel
Inverter Based IPQC for Microgrid
Maddala Uadykiran1
| A Durga Prasad
1PG Scholar, Department of EEE, Sir C R Reddy College of Engineering, Eluru, India.
2Assistant Professor, Department of EEE, Sir C R Reddy College of Engineering, Eluru, India.
To Cite this Article
Maddala Uadykiran and A Durga Prasad, “Power Quality Improvement with Multilevel Inverter Based IPQC for
Microgrid”, International Journal for Modern Trends in Science and Technology, Vol. 05, Issue 07, July 2019, pp.-39-43.
Article Info
Received on 07-June-2019, Revised on 11-July-2019, Accepted on 17-July-2019, Published on 21-July-2019
A micro grid is a hybrid power system consists of several distributed resources and local loads .Now a
days with increasing on a day to day life micro grid plays a vital role in power generation using Renewable
Energy Sources. Usage of power electronic devices in a micro grid results in harmonic generation and leads to
various power quality issues. Inorder to overcome voltage fluctuations and over current a magnetic flux
control based variable reactor is proposed. The performance of IPQC can be verified by using
MATLAB/SIMULINK.
KEYWORDS: Power Quality Improvement, Microgrid, IPQC,
Copyright © 2019 International Journal for Modern Trends in Science and Technology
All rights reserved.
I. INTRODUCTION
The strength is neither be created nor destroyed
alternatively it are frequently regenerate from one
sort to a different. The technology of AN energy is
nothing then again the conversion of various
one-of-a-kind sorts of energy into AN power. The
electric powered energy is generated in bulk at the
producing stations that are referred to as strength
stations. The generated strength is demanded by
means of the customers. This purpose due to the
fact of electricity losses and strength quality
troubles inside the transmission lines FACTS
machine is added to cut lower back such issues.
small grid ends up in positive distribution in
geographic vicinity all distribution consists of
tremendous electricity processor to control and
display the facility trade between the grids [1-3].
once such processor get definitely exploited it ends
up in high electricity great problems and strength
consumption with the aid of creating slender band
verbal exchange and native administration system
full small grid is exploited with marginal
investment. A forty eight pulse structure electrical
converter used to be developed by way of cascading
many devices of 3 degree diode clamped shape
electrical converter with the help of section moving
electrical device. It ends up in high fee and
prolonged delays this motive serious deficiency in
power transmission capability whereas
distribution [4]. Interline Power Flow Controller is
one in each of the advanced controller in versatile
AC equipment mechanism controller it completely
compensates collection and manages strength waft
inside the machine [5].
To at the equal time administration the facility
flow 2 convertor model d-q orthogonal was once
added inside the microgrid. By ability that of
transmission attitude version collection voltage is
inject within the administration vicinity and
ABSTRACT
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2. 40 International Journal for Modern Trends in Science and Technology
Maddala Uadykiran and A Durga Prasad : Power Quality Improvement with Multilevel Inverter Based IPQC for Microgrid
therefore the machine receives over paid [6].
Microgrid ends up in fine distribution in geographic
place all distribution consists of effective energy
inside the management vicinity processor to
manipulate and monitor the facility alternate
between the grids. once such processor get
absolutely exploited it ends up in high energy
satisfactory issues and power consumption via
growing slender band verbal exchange and native
management formula full small grid is exploited
with marginal investment and principally small
grid are regularly capable to disconnect from the
microgrid masses from the disturbance and
protects the transmission from harmonics [7]. By
grid interfacing convertor machine the traditional
sequence and parallel shape is customized. 2 3
phase 4 leg inverters is tend to construct grid
interfacing machine to compensate harmonic
contemporary it will enlarge the complication and
losses inside the gadget [8]-[9]. Distributed
generator now not solely inject power to the grid it
conjointly enhance strength quality. By capability
that of hunch management technique it
autonomously compensates voltage unbalances
lively and reactive hunch administration [10].A
bendy AC distribution system targets to increase
the facility fine and reliableness in microgrid, the
planning of administration algorithms and
prolonged kalman filters is supposed for frequency
chase and to extract harmonic in grid voltage and
cargo modern-day in small grid.
By minimizing the complete system planning and
operation cost and price of load shedding co-
optimization of electricity device is taken over to
enlarge the monetary and reliability of the grid [11].
The main advantage of multilevel inverters is
that the output voltage can be generated with a low
harmonics. Thus it is admitted that the harmonics
decrease proportionately to the inverter level. For
these reasons, the multilevel inverters are desired
for immoderate electricity applications[12].
However, there is no scarcity of disadvantages.
Their manipulate is a complete lot higher
problematic and the methods are despite the fact
that now now not greatly used in industry. In this
paper, modeling and simulation of a multilevel
inverter the use of Neutral Point-Clamped(NPC)
inverters have been performed with motor load the
usage of Simulink/ MATLAB program. In the first
section multilevel inverter manipulate strategies
are presented earlier than to element a locate out
about of seven-level inverter in the 2nd section.
Total Harmonic Distortion (THD) is mentioned in
the 1/3 section. The goal is to highlight the
restriction at which the multilevel inverters are no
longer effective in decreasing output voltage
harmonics [13, 14].
II. IPQC
A. System Configuration
The novel IPQC can be established in sequence
and parallel in microgrid or factor of frequent
coupling (PCC). For simplicity, the IPQC is
established in PCC. Fig. 8 indicates the
three-phase special gadget configuration of the
IPQC with transformer and inverter. and
characterize the source voltage and impedance of
conventional electricity supply, respectively. The
passive filters, which have the function of
absorbing the harmonics, are shunted in each
sides. The principal winding of a transformer is
inserted in collection between the conventional
strength utility and the microgrid, whereas the
secondary winding is linked with a voltage-source
PWM converter. is the voltage of the dc aspect of
the inverter. The microgrid consists of a harmonic
load, a photovoltaic mobilephone system, a battery
storage system, and a regular load. The proposed
IPQC has the following functions.
Fig.1. Circuit of the Proposed IPQC.
B. Power Flow Control
When the strength glide control and the fault
cutting-edge limiter are of concern, only the vital is
taken into account. In phrases of the previous
analysis, the primary winding well-knownshows
adjustable impedance + (1 − α) . With the alternate
in coefficient α, the equivalent impedance of the
main winding can be achieved, which is shown in
Table I. Therefore, when the foremost winding is
linked in collection in circuit, it can be utilized to
manage the strength waft between the

3. 41 International Journal for Modern Trends in Science and Technology
Maddala Uadykiran and A Durga Prasad : Power Quality Improvement with Multilevel Inverter Based IPQC for Microgrid
conventional power utility and the microgrid or the
inner electricity drift of the microgrid. The
schematic of power float control is proven in Fig. 9
when the novel variable reactor is connected in
series between the sending and receiving ends.
Suppose that the equal impedance + (1 − α) of the
variable reactor is R + jX. In phrases of the vector
sketch in Fig.9, the following equations can be
obtained: two
Fig 2: Power flow control principle and its
vector diagram.
C. Multilevel Inverter
Multilevel electrical energy conversion used to be
once as quickly as first introduced extra than two
many years ago. The not unusual thinking consists
of making use of a greater extent of energetic
semiconductorswitches to feature the energy
conversion in small voltagesteps. There are a
number of blessings to this approach
whencompared with the traditional power
conversion approach.The smaller voltage steps
lead to the manufacturing of higher powerquality
waveforms and moreover avert voltage (dv/dt)
stress onthe load and the electromagnetic
compatibility concerns.Another fundamental
characteristic of multilevel converters is that
thesemiconductors are wired in a series-type
connection, whichallows operation at larger
voltages. However, the sequence connection is
generally made with clamping diodes, which
eliminatesovervoltage concerns. Furthermore,
thinking about the switches are nottruly sequence
connected, their switching can be staggered,
whichreduces the switching frequency and for this
purpose the switching losses.However, the most
currently usedinverter topologies, which are in the
important addressed as relevant multilevel
inverters, are cascade converter,
neutral-pointclamped (NPC) inverter, and flying
capacitor inverter.Some features for these new
converters embody industrial drives, flexible ac
transmission structures (FACTS),and automobile
propulsion as verified in Fig.12. One vicinity the
place multilevelconverters are more regularly than
no longer appropriate is that of renewable
photovoltaic electrical energy that effectivity and
electrical strength first-rate are of wonderful
worries for the researchers
Fig.3.single leg of five level NPC inverter.
III. MATLAB/SIMULINK RESULTS
Fig 4: Proposed IPQC with MLI.
Fig 5: proposed MLI system.

4. 42 International Journal for Modern Trends in Science and Technology
Maddala Uadykiran and A Durga Prasad : Power Quality Improvement with Multilevel Inverter Based IPQC for Microgrid
Fig 6: load voltage response before and after
MLI based IPQC operation.
(a)
(b)
Fig 7: Current THD values without IPQC
(a)
(b)
Fig 8: Current THD values without IPQC
IV. CONCLUSION
The cascaded electrical converter change
indicators square measure generated victimisation
triangular-sampling current day controller; it gives
a dynamic typical overall performance under
transient and regular u . s . a . conditions,
doctorate analysis additionally inner the IEEE
standards. quick real-power idea specially based}
cascaded development electrical converter based
totally definitely IPQC is linked within the
distribution network at the PCC through filter
inductances and operates in a very manage
system. A cascaded construction voltage furnish
electrical converter pretty especially primarily
based IPQC victimisation quickly proper power
controller is located to be a desirable choice for
cable getting to know to compensate harmonics,
reactive electricity and electricity trouble with the
IRP controller reduces harmonics and offers
reactive electrical energy compensation thanks to
non-linear load currents; as a stop end result
provide current(s) end up curving and crew spirit
strength challenge is in addition executed below
each transient and consistent state conditions.
This paper has conferred a unique variable reactor
supported the magnetic flux management. A
electrical machine with air gap is chosen, and
therefore the coil modern of the electrical
computing device is detected. A voltage-sourced
electrical converter is utilized to comply with the
first present day to provide each different current,
that is injected to the secondary. as quickly as the
injected present day is adjusted, the equal
resistance of the first winding of the electrical
system can modification incessantly. In phrases of
the novel variable reactor, a special IPQC splendid
for microgrid is projected. the first winding famous
0 0.1 0.2 0.3 0.4 0.5
-400
-200
0
200
400
Selected signal: 25 cycles. FFT window (in red): 2 cycles
Time (s)
0 2000 4000 6000 8000 10000
0
5
10
15
Frequency (Hz)
Fundamental (50Hz) = 229.2 , THD= 18.76%
Mag(%ofFundamental)
0 0.1 0.2 0.3 0.4 0.5
-400
-200
0
200
400
Selected signal: 25 cycles. FFT window (in red): 2 cycles
Time (s)
0 2000 4000 6000 8000 10000
0
0.5
1
1.5
2
2.5
Frequency (Hz)
Fundamental (50Hz) = 460.7 , THD= 2.52%
Mag(%ofFundamental)
0 0.1 0.2 0.3 0.4 0.5
-10
0
10
20
Selected signal: 25 cycles. FFT window (in red): 2 cycles
Time (s)
0 2000 4000 6000 8000 10000
0
0.5
1
1.5
2
2.5
3
Frequency (Hz)
Fundamental (50Hz) = 13.95 , THD= 1.76%
Mag(%ofFundamental)
0 0.1 0.2 0.3 0.4 0.5
-10
0
10
20
Selected signal: 25 cycles. FFT window (in red): 2 cycles
Time (s)
0 2000 4000 6000 8000 10000
0
1
2
3
4
5
6
7
Frequency (Hz)
Fundamental (50Hz) = 6.941 , THD= 7.49%
Mag(%ofFundamental)

5. 43 International Journal for Modern Trends in Science and Technology
Maddala Uadykiran and A Durga Prasad : Power Quality Improvement with Multilevel Inverter Based IPQC for Microgrid
adjustable resistance, that performs the function of
strength go with the flow management, fault
present day electric circuit, and voltage
compensation to elementary.
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