Micro-inverter for integrated grid-tie photovoltaic module using resonant controller

Abstract

SUMMARY Two‐stage isolated converters for photovoltaic (PV) applications commonly employ a high‐frequency transformer (HFT) on the DC–DC side, submitting the DC–AC inverter switches to high voltages and forcing the use of insulated‐gate bipolar transistors instead of low‐voltage and low‐loss metal‐oxide‐semiconductor field‐effect transistors. This paper shows the modeling, control and simulation of a single‐phase full‐bridge inverter with HFT that can be used as part of a two‐stage converter with transformerless DC–DC side or as a single‐stage converter (simple DC–AC inverter) for grid‐connected PV applications. The inverter is modeled to obtain a small‐signal transfer function used to design the P + Resonant current control regulator, whose main advantages are the simplicity for implementation in single‐phase systems and zero steady state error with sinusoidal current. A high‐frequency step‐up transformer results in low‐voltage switches and better efficiency compared with converters in which the transformer is used on the DC–DC side. Simulations and experimental results with a 200‐W prototype are shown. Copyright © 2013 John Wiley & Sons, Ltd.

Enhanced low‐voltage ride‐through capability of flying capacitors inverter using model predictive control

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