Fuzzy-Logic-Controller-Based
SEPIC Converter for
Maximum Power Point Tracking
ABSTRACT:
This paper presents a fuzzy logic controller
(FLC)-based single-ended primary-inductor converter (SEPIC) for maximum power
point tracking (MPPT) operation of a photovoltaic (PV) system. The FLC proposed
presents that the convergent distribution of the membership function offers
faster response than the symmetrically distributed membership functions. The
fuzzy controller for the SEPIC MPPT scheme shows high precision in current
transition and keeps the voltage without any changes, in the variable-load
case, represented in small steady-state error and small overshoot. The proposed
scheme ensures optimal use of PV array and proves its efficacy in variable load
conditions, unity, and lagging power factor at the inverter output (load) side.
The real-time implementation of the MPPT SEPIC converter is done by a digital
signal processor (DSP), i.e., TMS320F28335. The performance of the converter is
tested in both simulation and experiment at different operating conditions. The
performance of the proposed FLC-based MPPT operation of SEPIC converter is
compared to that of the conventional proportional–integral (PI)-based SEPIC
converter. The results show that the proposed FLC-based MPPT scheme for SEPIC
can accurately track the reference signal and transfer power around 4.8% more
than the conventional PI-based system.
KEYWORDS:
1. DC–DC power converters
2. Fuzzy control
3. Photovoltaic(PV) cells
4. Proportional–integral (PI) controller
5. Real-time system.
SOFTWARE: MATLAB/SIMULINK
BLOCK DIAGRAM:
Fig. 1. Overall control scheme for the
proposed FLC-based MPPT scheme for the SEPIC converter.
CONCLUSION:
An
FLC-based MPPT scheme for the SEPIC converter and inverter system for PV power
applications has been presented in this paper. A prototype SEPIC
converter-based PV inverter system has also been built in the laboratory. The
DSP board TMS320F28335 is used for real-time implementation of the proposed FLC
and MPPT control algorithms. The performance of the proposed controller has
been found better than that of the conventional PI-based converters.
Furthermore, as compared to the conventional multilevel inverter, experimental
results indicated that the proposed FLC scheme can provide a better THD level at
the inverter output. Thus, it reduces the cost of the inverter and the
associated complexity in control algorithms. Therefore, the proposed FLC-based
MPPT scheme for the SEPIC converter could be a potential candidate for
real-time PV inverter applications under variable load conditions.
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