High-Step-Up and
High-Efficiency Fuel-Cell Power-Generation System With Active-Clamp Flyback–Forward
Converter
ABSTRACT:
A high-efficiency fuel-cell power-generation system with
an active-clamp flyback–forward converter is presented in this paper to boost a
12-V dc voltage into a 220-V 50-Hz ac voltage. The proposed system includes a
high-efficiency high-step-up interleaved soft-switching flyback–forward
converter and a full-bridge inverter. The front-end active-clamp
flyback–forward converter has the advantages of zero-voltage-switching
performance for all the primary switches, reverse-recovery-problem alleviation
for the secondary output diodes, large voltage-conversion ratio, and small input-current
ripple. Furthermore, there are two coupled inductors in the proposed converter.
Each coupled inductor can work in the flyback mode when the corresponding main
switch is in the turn-on state and in the forward mode when it is in the
turnoff state, which takes full use of the magnetic core and improves the power
density. In addition, the full-bridge inverter with an LC low-pass
filter is adopted to provide low-total-harmonic-distortion ac voltage to the
load. Therefore, high-efficiency and high-power density conversion can be
achieved in a wide input-voltage range by employing the proposed system.
Finally, a 500-W prototype and another 1-kW converter are implemented and
tested to verify the effectiveness of the proposed system.
KEYWORDS:
1.
Active clamp
2.
Fly back–forward converter
3.
Fuel cell generation system.
SOFTWARE: MATLAB/SIMULINK
CIRCUIT DIAGRAM:
Fig.
1. Proposed high-efficiency fuel-cell power-generation system
CONCLUSION:
In
this paper, an interleaved high-step-up ZVS flyback– forward converter has been
proposed for the fuel-cell power generation system. The voltage doubler
rectifier structure is employed to provide a large voltage-conversion ratio and
to remove the output-diode reverse-recovery problem. Furthermore, ZVS
soft-switching operation is realized for all the primary active switches to
minimize the switching losses. In addition, the input-current ripple is small
due to the interleaved operation and the current-fed-type configuration. The
steady state operation analysis and the main circuit performance are discussed
to explore the advantages of the proposed converter in a high-efficiency
high-step-up power-generation system. Finally, a 500-W 12-V dc to 220-V ac
system is employed and another 1-kW prototype operated at 100 kHz is tested as examples
to illustrate the important design guidelines of the proposed converter.
Experimental results have demonstrated that the proposed system is an excellent
power-converter system for fuel-cell applications, featuring high efficiency,
high-step up ratio, and high power density.
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