To Diminish the Voltage Sag Replaced DVR with Generalized Modulation Strategy for Matrix Converter

International Research Journal of Engineering and Technology (IRJET) e-ISSN: 2395 -0056
Volume: 04 Issue: 06 | June -2017 www.irjet.net p-ISSN: 2395-0072
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To Diminish the Voltage Sag Replaced DVR with Generalized
Modulation Strategy for Matrix Converter
Namrata Gupta1, Manish Awasthi2
1M. Tech Student, Dept. of Electrical Engineering, JNCT College, Rewa (MP), India
2Assistant Professor Dept. of Electrical Engineering, JNCT College, Rewa (MP), India
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Abstract - In the earlier period, the Power Quality (PQ) has
developed into critical problem in mechanized industries and
sensitive load centers. The voltage quality is most important
part of the PQ. The voltage instability is generated in the form
of voltage sag, swell and harmonics. In the past few years, the
power electronic has been proposed the solutions to avoid
these problems. The Dynamic Voltage Restorer (DVR) is the
solutions to diminish the voltage sag. Dynamic Voltage
Restorer (DVR) is used to protect sensitive loads against
generated voltage disturbances. It is a solution for power
system applications. The proposed model in this paper
replaces the conventional AC-DC-AC converter by a Matrix
Converter therefore avoiding bulky energy storage devices;
though retain the knack to compensateforindistincttimewith
very high power density. It protects sensitive loads from the
various types of disturbances of the power supply.
Key Words: Dynamic voltage restorer (DVR), Matrix
converter, Matlab/Simulink, Voltage sags, Voltage swells.
1. INTRODUCTION
DVR is of great importance in present day’s power system.
DVR is used to protect sensitive loads against voltage
disturbance can occurs into two forms either voltage or
voltage swell. it is a type of forceful or solution of power
system application fault at either the transmission or
distribution level may cause voltage sag and swell in the
entire system or a large part of it. Voltage sag occurs at any
time in the system. The ratio of the amplitude is 10-90%and
the time duration can take a half cycle of one minute [1].
1.1 Voltage sag
Voltage sag is defined as the drop of RMS voltage among
0.1 p.u. and 0.9 p.u. and durable between 0.5 cycles to 1
minute. Voltage sag are typically cause by the fault of the
system. It is caused by asymmetrical line to line, single and
double-line-to-ground and symmetrical three phase faults
effects on sensitive loads, the DVR injects the voltages to
restore and maintain the sensitive to its supposed value The
insertion power of the DVR with minimum power for
compensation purposes can be achieved by selecting an
amplitude and phase angle.
Fig -1: Voltage sag
Voltage sag and swell can cause by the failing of the
sensitive equipment like shutdown,largeunbalancecurrent,
fuses or trip breakers. It may be very expensive for the
customers. With the use of Dynamic Voltage restorer it
Dynamic Voltage restorer can be eliminate this problem.
2. DYNAMIC VOLTAGE RESTORER (DVR)
A Dynamic Voltage Restorer (DVR) is series connected
devices that inject supply voltage into the system; to control
the load voltage. DVR was installed at the first time in 1996.
Generally it is installed in a distribution system between the
supply and load feeder. Its most important function is to
quickly boost up the load voltage in form of disturbance in
order to avoid any power disruption in load. There are
varieties of circuit topology and control scheme that can be
used to apply a DVR. In the addition of voltage sags and
swells compensation, DVR has some other features such as:
line voltage harmonics compensation, reduction of
transients in voltage and fault current limitations.
The basic configuration of DVR is consists of a Booster
transformer, a Harmonic filter, a Voltage Source Converter
(VSC) and a Control & Protection system as shown in Fig-2.
Fig -2: Dynamic Voltage Restorer (DVR)

Dynamic Voltage Restorer (DVR) is used to protect the
sensitive loads against voltage instability. So the
conservative DVR will be very huge, making its power
density will be smaller, requiring continuous maintenance.
As the compensation period increases the size the
conventional DVR also increases.Theproposedmodel in this
paper replaces the conventional AC-DC-AC converter by a
Matrix Converter due to avoiding bulky energy storage
devices.
Dynamic Voltage Restorer (DVR) may be consisting with
the combination of various parts, like;
1. Injection /Booster transformer
2. Harmonics Filter
3. Voltage Source Converter
4. Energy Storage Device/ Control System
5. By–pass Equipment
2.1 Injection / Booster transformer
The Injection / Booster transformer is a particularly
designed transformer that limits the coupling of noise and
transient energy from the source side to the load side.
Its main tasks are:
1) It connects the DVR to the distribution network via
the HV-windings and transforms and couples the
injected compensating voltages generated by the
voltage source converters to the incoming supply
voltage.
2) In addition, the Injection / Booster transformer
serves the purpose of isolating the Load from the
system (VSC and control mechanism).
2.2 Harmonic filter
The main operation of harmonic filter is to maintain the
harmonic voltage content generated by the voltage source
converters (VSI) to the acceptable level (i.e., Eliminate the
harmonics with high frequency switching).It has a small
approximate rating 2% of the load MVA.
2.3 Voltage source converter
The converter is principally liable a Voltage Source
Converter (VSC), which is Pulse width modulates(PWM)the
DC from the DC-link/storage to AC-voltages injectedintothe
system. A Voltage Source Converter (VSC) is a power
electronic device which is consists by a storage device and
switching device, which can be generated a sinusoidal
voltage or sinusoidal waveform at any essential frequency,
magnitude, and phase angle. In the application of DVR, the
Voltage Source Converter (VSC) is used to momentarily
change in the supply voltage or to generate a part of the
supply voltage which is absent.
2.4 Energy storage device/ Control system
A DC-link voltage is used in the VSC to produce an
AC voltage into the network and during a majority of
voltage sag active power booster is necessary to re-
establish the supply voltages.
The main task of dc charging circuit is:
1. The first task is to charge the energy source
after a sag compensation event.
2. The second task is to maintain dc link voltage
at the nominal dc link voltage.
2.5 By-Pass Equipment
During faults, overload and service a bypasspathforthe
load current has to be ensured.
3. EQUIVALENT CIRCUIT OF DVR
Fig -3: Equivalent Circuit of DVR
The equivalent circuit of the DVR is shows in Fig-3,whenthe
source voltage is fall or raise, the Dynamic Voltage Restorer
(DVR) inject a series voltage V
inj
by injection transformer so
that the desired magnitude of load voltage V
L
can be
maintained. The series injected voltage of the DVR can be
written as:
V
inj
= V
L
+ V
s
(1)
Where,
V
L
= Desired Load Voltage Magnitude
V
s
= Source Voltage During Sags/Swells Condition
I
l
= Load Current
It is given by,
Il = (2)

4. LOCATION OF DVR
Fig -4: Location of DVR
The supplement of a DVR at the low voltage 4-wire 440 V
level is shown in Fig-4. The increase in impedance by
insertion of a small rated DVR can be significant for the load
to be protected from voltage dips. Thereby, the per cent
change in the impedance (Zincrease, %) in can be increased
by several hundred per cent.
Fig -5: Operational Flow Chart of DVR
5. MATRIX CONVERTER
The matrix converter is consists by the combination of 9 Bi-
directional (18 IGBT + 18 Diodes) switches that allocate any
output phase to be linked to any input phase. The circuit
scheme is shown in Fig-6. The figure corresponds to the 3x3
way. Matrix converter can convertAC/ACelectrical powerin
direct form and its needs to be protected against the
overvoltage. The over current that may be critical for its
semiconductor devices. It is totally operates upon variable
frequency & variable voltage.
Fig -6: Matrix Converter
6. Switching Configuration
Switching Configuration
S.No. Switches Configuration Description
1. Diode bridge
with a single
IGBT
Its conduction losses are
high.
Two diodes and a
switching device is
conduct
switching device per
switch is only one
2. Two anti-
paralleled
IGBT with
series diodes
Conduction losses canbe
generated for only 1
diode and 1 switching
device
It can be operate on both
Common Collector &
Common Emitter
Both of the devices can
be gated from same
isolated power supply
Direction of Current
Flow, Can be Controlled
Useful for most current
commutation strategy
3. Two anti-
paralleled
NPT IGBT’s
with reverse
blocking
capability
It is use to the Pair of
reverse blocking IGBTs
Conduction losses are
reduced.
Reverse recovery can be
concern
The design of Power
SemiconductorModuleis
simple.
It Can Control Direction
of Current Flow

5.1 Single Phase Matrix Converter
Fig -7
6. COMMUTATION METHOD IN MATRIX
CONVERTER
The commutation has always dynamically controllable. It is
important that two bidirectional switches are should not
switched on at the same. This result of the capacitor input is
short circuit and inductive load is open circuit. We have
different types of commutation (with matrix converter)
available:
6.1 Dead Time Commutation
The Dead time commutation method is used in the part
of inverter. It means that load current go throw anti-parallel
diode through the dead time period.Deadtimecommutation
method is useless in the case of matrix converter. Attheload
side results can be measure with the condition of open
circuit.
6.2 Current Commutation based on Multiple Steps
Current Commutation based on Multiple Steps isusesin
bidirectional switches. These are consistent in current
commutation. It can control the current direction. This
commutation technique is helped on the knowledge of
output current direction. This technique provides reliable
current. The active gate drives the calculated current
direction.
7. SIMULATION RESULT
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Fig -8: P.U. Voltage at load point, with three phase fault,
without DVR
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Fig -9: P.U. Voltage at load point, with three phase fault
8. CONCLUSIONS
The modeling and simulationofDynamicvoltageRestorer
(DVR) are presented by the usage of MATLAB/
SIMULATION. The simulation shows the satisfactory
performance of DVR in The case of voltage sag and swell.
Simulation result ma shows effective custom power of
voltage sag and swell. The simulation carried out the
better voltage regulation capability of DVR. Dynamic
voltage Restorer (DVR) is handling both balanced and
unbalanced position without any problem.
The main advantage of DVR is consider To be
efficient result has been provided with low cost, fast
response, compact size and its control is simple. As a
result This DVR model can use to restore load voltage in
The case of balance and unbalance condition of voltage
sags and swells.
ACKNOWLEDGEMENT
I express my thanks to Almighty for providing me
inspiration, strength, energy and patience to start and
accomplish my work with the support of all concerned a few
of them I am trying to acknowledge. I heartily and
courteously thank my guide Mr. MANISH AWASTHIwho has
been main source of inspiration to guide this work
throughout the course of the work. He is a person with
tremendousforce, resourceful,creativityandfriendlynature.
He proved himself to be the best guide by the way of
inspiring to work in right direction, presenting research
papers in seminars and conferences. I thank Mr MANISH
AWASTHI, Department of Electrical Engineering Jawaharlal
Nehru College of technology, Rewa (M.P) For helping me in
all ways for registering me as M.Tech. Student, for providing
laboratory facilities. I am also thankful to fortheirassistance
and help. I express my thanks to all my colleagues for their
help and throughout support. Last butnotleast,Iexpress my
thanks to my family for all support, inspiration and love
provided to me with all inconveniencies caused because of
my engagement in this work.

REFERENCES
[1] C. Benachaiba, S. Dib O. Abdelkhalek, B. Ferdi. Voltage
quality improvement using DVR.
[2] IEEE Std. 1159-1995. Recommended Practice for
Monitoring Electric Power Quality.
[3] J.G. Nielsen, M. Newman, H. Nielsen and F. Blaabjerg.
2004. Control and testing of a dynamic voltage restorer
(DVR) at medium voltage level. IEEE Trans. Power
Electron. 19(3): 806 May
[4] T. Devaraju, V.C. Veera Reddy, M. Vijaya Kumar
performance of DVR under different voltage sag and
swell condition
[5] B.H. Li, S.S. Choi, D.M. Vilathgamuwa, “Design
Considerations on the Line-Side Filter Used in the
Dynamic Voltage Restorer”, IEE Proc. Gener.
Transmission Distrib., Issue 1, Vol. 148, pp. 1-7, Jan.
2001.
[6] M. N. Tandjaoui, C. Benachaiba, O. Abdelkhalek
Mitigation of voltage sags/swells unbalanced in low
voltage distribution systems
[7] A. Imam, T. Habetler, R. Harley and D. Divan, “Condition
monitoring of electrolytic capacitor in power electronic
circuits using adaptive ﬁlter modeling,” IEEE 36th
Annual Power Electronics Specialists Conference,2005,
pp. 601-607.
[8] B. Wang and G. Venkataramanan, “Dynamic Voltage
Restorer utilizing a matrix converter and flywheel
energy storage,” IEEE Transactions on Industry
Applications, Jan-Feb 2009, vol. 45, pp. 222-231.

To Diminish the Voltage Sag Replaced DVR with Generalized Modulation Strategy for Matrix Converter

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To Diminish the Voltage Sag Replaced DVR with Generalized Modulation Strategy for Matrix Converter