ABSTRACT:
In
this paper a full soft-switching high step-up DC-DC converter is introduced as
an alternative approach to module integrated converters for photovoltaic
applications. The presented operation principle and key equations can be used
as design guidelines for component and parameter estimation in practical
applications. The proposed DC-DC converter was verified by help of simulations
and experiments. Power loss analysis based on the semiconductor datasheet
values showed that the converter tends to achieve an efficiency of 92. 8% at
the maximum power point.
KEYWORDS:
1. DC-DC
power conversion
2. Photovoltaic power systems
3. MOSFET switches
SOFTWARE: MATLAB/SIMULINK
CIRCUIT DIAGRAM:
Fig.
1: Generalised topology of the proposed DC-DC converter.
EXPECTED SIMULATION RESULTS:
Fig. 2: Simulated voltage and current
waveforms of MOSFET SI (a), MOSFET Tl (b), transformer
primary
(c) as well as the input and output voltage and current waveforms (d).
Fig.
3: Converter regulation characteristics at different irradiation levels (a) and
cell temperatures (b).
Fig.
4: Experimental voltage and current waveforms of Tl MOSFET (a), SI MOSFET (b)
and S2
MOSFET
(c).
Fig.
5: Experimental waveforms of the input (a) and output (b) voltage and current.
CONCLUSION:
The
proposed high step-up DC-DC converter allows ZVS of the inverter switches and
ZCS of the rectifier switches. The operation principle presented and the
mathematical analysis of the converter can be used as design guidelines for
component and parameter estimation in practical applications. The operation of
the converter was verified with the 300 W experimental prototype and the experimental
waveforms were found to correspond to the estimated ones. The major limitation
of the converter lies in the diodes connected in series to the inverter
transistors. The static losses in these diodes will contribute a major portion
of the total converter losses. In the future these diodes will be replaced by
MOSFETs, external snubber capacitors for rectifier switches will be introduced
and the implementation possibilities of wide-bandgap semiconductors will be
also addressed.
REFERENCES:
[1] Walker, G.R.; Sernia, P.C., "Cascaded DC-DC converter
connection of photo voltaic modules", 33rd Annual Power Electronics
Specialists Conference PESC'2002, vol. I, pp.24-29, 2002.
[2] Forcan, M.; Tusevljak, J.; Lubura, S.; Soja, M.,
"Analyzing and Modeling the Power Optimizer forBoosting Efficiency of PV
Panel", IX Symposium Industrial Electronics INDEL'2012, pp. 198-193, Banja
Luka, November 01-03,2012.
[3] Kasper, M.; Bortis, D.; Friedli, T.; Kolar, J.W., "Classification
and comparative evaluation of PV panel integrated DC-DC converter
concepts," Power Electronics and Motion Control Conference (EPEIPEMC),
2012 15th International, pp.LSle.4-1,LSle.4-8, 4-6 Sept. 2012.
[4] Christian Peter Dick "Multi-Resonant Converters as
Photovoltaic Module-Integrated Maximum Power Point Tracker", PhD Thesis
2010, available: http://darwin.bth.rwth-aachen.de/opus3/volltexte/20
1 0/3267 /pdf/3267 .pdf
[5] Kasper, Matthias; Ritz, Magdalena; Bortis, Dominik; Kolar,
Johann W., "PV Panel-Integrated High Step-up High Efficiency Isolated GaN
DC-DC Boost Converter," Proceedings of 2013 35th International Telecommunications
Energy Conference 'Smart Power and Efficiency'
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