A High-Gain and High-Efficiency Photovoltaic Grid-Connected Inverter with Magnetic Coupling

Conventional photovoltaic (PV) grid-connected systems consist of a boost converter cascaded with an inverter, resulting in poor efficiency due to performing energy processing twice. Many pseudo DC-link inverters with single energy processing have been proposed to improve system efficiency and simpli...

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Bibliographic Details
Published in:Micromachines (Basel) 2022-09, Vol.13 (10), p.1568
Main Authors: Chang, Chien-Hsuan, Cheng, Chun-An, Cheng, Hung-Liang, Chang, En-Chih
Format: Article
Language:English
Subjects:
Alternative energy sources
Circuits
Climate change
Conduction losses
Coupling
Efficiency
high efficiency
High gain
inverter
Inverters
magnetic coupling
Photovoltaic cells
Solar energy industry
Voltage gain
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Summary:Conventional photovoltaic (PV) grid-connected systems consist of a boost converter cascaded with an inverter, resulting in poor efficiency due to performing energy processing twice. Many pseudo DC-link inverters with single energy processing have been proposed to improve system efficiency and simplify circuits. However, their output voltage gain is limited by the non-ideal characteristics of the power diode, making them difficult to apply in high-output voltage applications. This paper proposes combining a boost converter with magnetic coupling and a full-bridge unfolding circuit to develop an inverter featuring high voltage-gain and high efficiency. According to the desired instantaneous output voltage, the high-gain boost converter and the full-bridge unfolding circuit are sequentially and respectively controlled by SPWM. A sinusoidal output voltage can be generated by performing energy processing only once, effectively improving the conversion efficiency. Magnetic coupling is adopted to increase the voltage gain of step-up, and the step-down function is realized by the full-bridge unfolding circuit to reduce conduction loss. Finally, a 500 W prototype was fabricated for the proposed high-gain inverter. The experimental results were used to verify the correctness of the theoretical analysis and the feasibility of the circuit structure.
ISSN:2072-666X
2072-666X
DOI:10.3390/mi13101568