The document proposes a matrix converter-based dynamic voltage restorer (DVR) system for power quality enhancement. The DVR uses a single matrix converter instead of a conventional AC/DC/AC converter. It is connected between the distribution feeder and load to mitigate voltage sags. The control system is based on dqo modeling of the matrix converter. It injects power from an energy storage device like a flywheel to restore the load voltage during sags. Simulation results show the DVR is able to effectively reduce sags and regulate the supply voltage, improving power quality.

1. DESIGN OF MATRIX CONVERTER BASED
DYNAMIC
VOLTAGE RESTORER FOR POWER QUALITY
ENHANCEMENT

2. ABSTRACT
 A new series power conditioning system using a matrix
converter is proposed. The proposed solution has utilized
a single AC/AC power converter for interface as an
conventional AC/DC/AC converter. The dynamic model is
used to design a vector control system that seamlessly
integrates functional of compensating load voltage and
managing energy storage during voltage sag and idling
modes. The purpose of matrix converter used in dynamic
voltage restorer (DVR) for power quality enhancement,
which is connected in between the feeder to secure the
electric power from sags. The DVR is based on dqo
algorithm which is discussed with matrix converter to inject
external supply into the feeder by means of a series
transformer. Harmonics are produced due to non-linear loads,
and it is filtered out by a filter which is connected at terminal
end of the system. The simulation results are carried out
by MATLAB and the performance of proposed method is
verified.

3. INTRODUCTION TO POWER QUALITY
 Power quality determines the fitness of
electric power to consumer devices.
Synchronization of the voltage frequency and
phase allows electrical systems to function in their
intended manner without significant loss of
performance or life.
 The power quality is main area should be deal in
power system in modern technology for using
equipment without any problems.
 The power quality enhancement must be needed
to protect the sensitive equipment from the fault
which occurs at generating station and
transmission lines.

4. POWER QUALITY PROBLEMS
 The power supply contains lot of power quality
issues like flickers, sags, swells, harmonics,
transients, and notching.
 In this voltage sag is main phenomena that causes
vulnerable to the power system. Due to sag,
the losses in machines get increases, sensitive
equipment gets fail, voltage regulation will be
affected, the circuit breaker trips without being
overloaded, speed of motor gets vary, and
makes the power system into imbalance condition.

5. DEFINITION AND CAUSES OF SAG
 The sag is nothing but reduction in
magnitude of sinusoidal wave.
 The sag causes due to lightning stroke,
switching of lines, non linear loads like
arc furnace, welding machines, weather
condition, falling of trees, animal
contacts, and insulation failures and short
circuit fault at the distribution feeder.

6. PROPOSED CONCEPT
A new series power conditioning
system(DVR) using matrix converter
is proposed in this project.
The purpose of matrix converter
used in dynamic voltage restorer
(DVR) for power quality
enhancement, which is connected in
between the feeder to secure the
electric power from sags.

7. BLOCK DIAGRAM OF DVR, AND SAGS IN THE
SUPPLY

8. OBJECTIVE
 The main objective of this project is to reduce the sag
and make the power supply into sag free.
 The device well known for reduction of voltage sag
is dynamic voltage restorer (DVR) had been
implemented as an advantage of series
compensation over the shunt compensation for
voltage stiff system.
 The mitigation of sags in sensitive equipment with
high power factor is quit enhanced. The energy storage
device normally required for eliminating the sag with
high power factor.
 The series compensator, dynamic voltage restorer
restore the supply voltage without sag by injecting
the external source into the feeder.

9. SYSTEM ARCHITECTURE

10. SYSTEM DESCRIPTION
 The system architecture based on the operational
conditions: which three requirements have been proposed in
the above figure
 1) To mitigate the voltage sag and recover storage
energy, bidirectional power flow is requiring.
 2) According to the nature of the load the system should
operate properly, so it must contain wide range of power
factor at converter end.
 3) The converter must have capability to operate in buck
mode, when the grid injection voltage is very low during fully
charged flywheel

11. MODELING OF MATRIX CONVERTER
 The matrix converter is necessary to operate as
bidirectional converter or switch. The proposed
matrix converter is indirect matrix converter (IMC) in
which it maintained DC link voltage positive and
allowing the current to be either in positive or
negative.
 The current source inverter is connected to the source
and voltage source inverter is connected to the grid.
 The matrix converter should operate according to
the flywheel supply from rotation. To maintain the
DC link voltage positive, displacement angle must
be limited to (-л/6, л/6),it is normally done by an
algorithm.

12. CONTROL CIRCIT DISCRIPTION

13. CONTROL ALGORITHM FOR MATRIX
CONVERTER
 The phase lock loop is implemented to
compare two non idling signals and gives mean
signal for protection of pulse with modulation
(PWM)
 The simulation is based on dqo algorithm in which
system is compare with reference voltage and error
voltage is produced, by converting into abc to
dqo algorithm as shown in above figure
 According to the error value, pulses are
generated to control the matrix converter to
inject the external source into the system. The
overall simulation diagram is shown in below
figure.

14. PROPOSED ARCHITECTURE OF THE DVR
SYSTEM.

15. CONCLUSIONS
 The method of DVR proposed in this project introduces matrix
converter , which neglects DC link based topology as used in back to
back converter.
 The implementation of phase lock loop which maintains the pulse
width modulation for control the matrix converter is proposed.
 The closed loop method proposed, to improve the dynamic
performance of the system. The modeling and control circuit is based
on dqo algorithm, in which sags are effectively reduced by the DVR.
 It will provides quickly excellent voltage regulation in power supply.
 The balance and unbalance voltage level gets regulated by appropriate
voltage is injecting and compensate the power supply.
 By this method, grid supply is maintained constant for all time . The
advantages of DVR are low cost, simple control circuit and it can mitigate
long duration voltage sags efficiently. The simulation of DVR using
MATLAB/SIMULINK has been presented and verified

16. REFERENCES
 [1] M. F. Mc Granaghan, D. R. Mueller, and M. J.
Samotyi,” V Voltage Sags in Industerial Systems,”
IEEE trans ind. A ppl., vol. 29, no. 2, pp. 397-403,
Mar/Apr. 1996.
 [2] A. kara, P . Dabler, D. Amhof , and H.
Gruning” Power Supply Quality Improvement
with A Dynamic Restorer (DVR)”, in proc .13
Annu .APEC (cat no 98CH36154), An aheim, ca,
1998, PP. 986-993
 [3] L. Gyugyi, C. D. Schauder, C. W . Edwards
and M.Sarkozii, ”Apparatus and Method for
Dynamic Voltage Restoration of Utility Distribution
Network ,”US. pattent 5 329 222, Jul. 1994