ABSTRACT:
In this paper, a Photovoltaic based Dynamic Voltage
Restorer (PV-DVR) is proposed to handle deep voltage sags, swells and outages
on a low voltage single phase residential distribution system. It can recover
sags up to 10%, swells up to 190% of its nominal value. Otherwise, it will
operate as an Uninterruptable Power Supply (UPS) when the utility grid fails to
supply. It is also designed to reduce the usage of utility power, which is
generated from nuclear and thermal power stations. A series injection
transformer is connected in series with the load when restoring voltage sag and
swell and it is reconfigured into parallel connection using semiconductor
switches when it is operating in UPS and power saver mode. The use of high step
up dc-dc converter with high-voltage gain reduces the size and required power
rating of the series injection transformer. It also improves the stability of
the system. The Fuzzy Logic (FL) controller
with two inputs maintains the load voltage by detecting the voltage variations through d-q
transformation technique. Simulation
results have proved the ability of the proposed DVR in mitigating the voltage sag, swell and
outage in a low voltage single phase residential distribution system.
KEYWORDS:
1.
Dynamic
Voltage Restorer
2.
Photovoltaic
3.
Voltage Sag
4.
Voltage Swell
5.
Outages
6.
High Step up
dc-dc Converter
7.
Fuzzy Logic
Controller
SOFTWARE: MATLAB/SIMULINK
BLOCK DIAGRAM:
Fig.
1. Structural block diagram of the proposed system.
EXPECTED SIMULATION RESULTS:
(a)
Supply
Voltage
(b)
Injected
Voltage
(c)
Load
Voltage
(d)
Load
Current
(e)
Load voltage THD
Fig.
2. Supply voltage, Injected voltage, Load voltage, Load Current and
Fig.
3. Load Voltage with PI controller
(a)
PV
array output voltage without low power boost converter
(b)
PV array output voltage with low power boost converter
Fig.
4. PV array output voltage without and with boost converter
Fig.
5. Output voltage of the high step up DC-DC converter
CONCLUSION:
This
paper proposed a new PV based DVR to reduce the energy consumption from the
utility grid. The design of a Dynamic Voltage Restorer (DVR) which incorporates
a PV array module with low and high power boost converters as a DC voltage
source to mitigate voltage sags, swells and outages in low voltage single phase
distribution systems using FL controller has been presented. The modeling and simulation
of the proposed PV based DVR using MATLAB simulink has been presented. The FL
controller utilizes the error signal from the comparator to trigger the
switches of an inverter using a sinusoidal PWM scheme. The proposed DVR utilizes
the energy drawn from the PV array and the utility source to charge the
battries during normal operation. The stored energies in battery are converted
to an adjustable single phase ac voltage for mitigation of voltage sag, swell and
outage. The simulation result shows that the PV based DVR with FL controller
gives better dynamic performance in mitigating the voltage variations. The
proposed DVR is operated in:
Standby
Mode: when the PV array voltage is zero and the inverter
is not active in the circuit to keep the voltage to its nominal value.
Active
Mode: when the DVR senses the sag, swell and outage. DVR
reacts fast to inject the required single phase compensation voltages.
Bypass
Mode: when DVR is disconnected and bypassed in case of maintenance
and repair.
Power
Saver mode: when the PV array with low step-up dc-dc converter
output power is enough to handle the load.
Further
work will include a comparison with laboratory experiments on a low voltage DVR
in order to compare simulation and experimental results. The multiple functions
of DVR require further investigation.
REFERENCES:
[1]
H.Ezoji, A.Sheikholeslami, M.Tabasi, and M.M.Saeednia, “Simulation of dynamic
voltage restorer using hysteresis voltage control,” European journal of scientific
research, vol. 27, pp. 152-166, Feb 2009.
[2]
F.A.L.Jowder, “Modeling and simulation of different system topologies for
dynamic voltage restorer using simulink,” in proc. EPECS ’09, 2009, p. 1-6.
[3]
R.Strzelecki, and G.Benysek, “Control strategies and comparison of the dynamic
voltage restorer,” in proc. PQ ‘08, 2008, p. 79-82.
[4]
P.Boonchiam, and N.Mithulananthan, “Understanding of dynamic voltage restorers
through MATLAB simulation,” Thammasat Int. J. Sc. Tech., Vol. 11, No.3, pp.
1-6, Sep 2006.
[5]
K.C.Bayinder, A.Teke, and M.Tumay, “A Robust control of dynamic voltage
restorer using fuzzy logic,” in proc. ACEMP ’07, 2007, p.55
