ABSTRACT:
In this study, a designed proportional-integral
(PI) controller and a fuzzy logic controller (FLC) that fix the voltage amplitude to a constant value of
380 V and 50 Hz for loads supplied from a wind/battery hybrid energy system are
explained and compared. The quality of the power produced by the wind turbine
is affected by the continuous and unpredictable variations of the wind speed.
Therefore, voltage-stabilizing controllers must be integrated into the system
in order to keep the voltage magnitude and frequency constant at the load
terminals, which requires constant voltage and frequency. A fuzzy logic-based
controller to be used for the voltage control of the designed hybrid system is
proposed and compared with a classical PI controller for performance
validation. The entire designed system is modeled and simulated using
MATLAB/Simulink GUI (graphical user interface) with all of its subcomponents.
KEYWORDS:
1.
Fuzzy logic
controller
2.
Proportional-integral
controller
3.
Renewable
energy
4.
Wind turbine
SOFTWARE:
MATLAB/SIMULINK
Figure 1. PV/battery renewable source.
EXPECTED SIMULATION RESULTS:
Figure 2. Power on the load: a) with a PI controller and b) with a FLC.
Figure 3. Results of the PI controller.
Figure 4. Results of the FLC.
Figure 5. PI controller results.
Figure 6. FLC results.
Figure 7. Vab−load variation for PI controller
Figure 8. Vab−load variation for the FLC.
Figure 9. Wind turbine V, I, active, and reactive power variations with PI system.
Figure 10. Wind turbine V, I, active, and reactive power variations with FLC system.
CONCLUSION:
The waveform of the loads was very similar to
the sinus wave form using both the PI and fuzzy logic controllers. The system
can fix the voltage on the loads at a constant value of 380 V regardless of
effects from the variations of the wind speed. The system frequency value is
steady at 50 Hz. According to the value of the wind speed, the used regulator
works effectively by turning on and off the batteries. The maximum overshoot
and settling time values of the FLC were much better than those of the PI controller.
The PI controller maximum overshoot voltage that can be reached is 392 V. This
value is 384 V with the FLC system. The PI controller’s setting time was 2 s;
this value was 0.05 s for the FLC. When the THD values are compared, it is seen
that both controllers had values in the standard ranges. However, the FLC’s
value was better than the PI’s, as was its sinus wave form. When the produced
energy is greater and the loads are low, the wind turbine must be arranged to
recharge the batteries. This can be done by the management of the energy. When
there is no wind, the loads are supplied only with batteries. When the
batteries are empty, the loads will have no energy supply. To prevent this
situation, a diesel generator can be added to the system or the system can be
supplied with energy by the main network.
REFERENCES:
[1] J. Peinke, P. Schaumann, S. Barth, Wind
Energy Proceedings of the Euromech Colloquium, Berlin-Heidelberg, Springer,
2007.
[2] Global Wind and Energy Council, Market
Forecast 2010-2014, available at: http://www.gwec.net/fileadmin/documents/Publications/Global
Wind 2007 report/market%20forecast%202010- 2014.JPG.
[3] M.R. Patel, Wind and Solar Power Systems,
Boca Raton, Florida, CRC Press, 2006.
[4] T. Ackerman, Wind Power in Power Systems, New
York, John Wiley and Sons, 2005.
[5] P.A. Stott, M.A.Mueller, “Modelling fully
variable speed hybrid wind diesel systems”, 41st International Universities Power
Engineering Conference, Vol. 1, pp. 212-216, 2006.
