ABSTRACT:
The changes in temperature and radiation
cause visible fluctuations in the output power produced by the photovoltaic
(PV) panels. It is essential to keep the output voltage of the PV panel at the
maximum power point (MPP) under varying temperature and radiation conditions.
In this study, a maximum power point tracking (MPPT) method has been developed
which is based on mainly two parts: the first part is adapting calculation block
for the reference voltage point of MPPT and the second one is Fuzzy Logic Controller
(FLC) block to adjust the duty cycle of PWM applied switch (Mosfet) of the
DC-DC converter. In order to evaluate the robustness of the proposed method,
Matlab/Simulink program has been used to compare with the traditional methods
which are Perturb & Observe (P&O), Incremental Conductance (Inc. Cond.)
and FLC methods under variable atmospheric conditions. When the test results
are observed, it is clearly obtained that the proposed MPPT method provides an increase
in the tracking capability of MPP and at the same time reduced steady state
oscillations. The accuracy of the proposed method is between 99.5% and 99.9%.
In addition, the time to capture MPP is 0.021 sec. It is about four times
faster than P&O and five times faster than for Inc. Cond. and, furthermore,
the proposed method has been compared with the conventional FLC method and it
has been observed that the proposed method is faster about 28% and also its
efficiency is about 1% better than FLC method.
KEYWORDS:
1.
PV
2.
MPPT methods
3.
FLC based MPPT
4.
DC-DC converter
SOFTWARE: MATLAB/SIMULINK
BLOCK DIAGRAM:
Fig. 1. Block diagram of the
designed system.
Fig. 2. The PV power with four MPPT algorithm.
Fig. 3. The speed of MPPT algorithms.
Fig. 4. The PV voltage with four MPPT algorithm.
Fig. 5. The generated PV current with four MPPT
methods.
Fig. 6. The reference voltage produced by the
MPPT algorithm.
Fig. 7. PV array current and load current.
Fig. 8. Fuzzy logic controller output (D).
Fig. 9. PV array voltage and load voltage.
Fig. 10. PV power for four different MPPT
techniques under variable irradiance (fixed temperature).
Fig. 11. PV currents for proposed MPPT technique.
Fig. 12. PV voltages for proposed MPPT technique
under variable irradiance (fixed temperature).
Fig. 13. PV power for four different MPPT
techniques under variable temperature (fixed irradiance).
Fig. 14. PV currents for proposed MPPT technique.
Fig. 15. PV voltages for proposed MPPT technique
under variable temperature (fixed irradiance).
Fig. 16. (a) P-V characteristics curve, (b)
Tracking global peak point for proposed MPPT technique.
CONCLUSION:
This study proposes a novel MPPT method
and the detailed performance comparison with commonly used methods such as
P&O, Incremental conductance and FLC techniques is achieved. Under sudden
change in atmospheric operating conditions, the proposed MPPT method performs
better performance than other methods to determine MPP. The efficiency of proposed
MPPT method is between 99.5% and 99.9%, while P&O is between 91% and 98%,
Inc. Cond. Is between 96% and 99% and FLC is between 98.8% and 99.4% for all case
studies. The proposed MPPT method has achieved the lowest oscillation rate at
the MPP compared to commonly used methods. This brings the method to the
forefront in terms of efficiency. The duration of the proposed MPPT technique to
reach a steady state has been measured as 0.021 sec. It is about four times
faster than P&O and five times faster than for Inc. Cond. and, furthermore,
the proposed method has been compared with the conventional FLC method and it
has been observed that the proposed method is faster about 28% than FLC method
this means the speed of proposed MPPT technique is the best. At the same time,
the amount of oscillation is very low compared to conventional methods. The
accuracy of the algorithm is high (%99.9 in many study cases) and also the
proposed method is easy to implement in the system.
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