proposes an isolated microinverter topology with preudo-DC link, it consists of an inverse-buck current-fed isolated dual-boost converter with a voltage doubler for the first stage, and a full-bridge inverter topology is designed for the secondary stage to realize the power transfer, high step-up function can be achieved, and 93% of conversion efficiency for the microinverter is obtained because of the utilization of large counts of components. Zero-voltage-switching (ZVS) operation and elimination of high-voltage stresses can be achieved for the power devices high peak efficiency of the boost-half-bridge converter is reported to be 97.0–98.2% over the wide input voltage range. In, a boost-half-bridge DC–DC converter cascaded with a full-bridge inverter using synchronized pulse-width modulation (PWM) is implemented for photovoltaic microinverter system and a plug-in repetitive current controller is provided to inject the sinusoidal current with a unity power factor to the AC grid. For two-stage microinverter, a high step-up DC–DC topology is adopted in the first stage to boost the PV DC voltage and realize the MPPT, and the second stage regulates the sinusoidal output current to the grid. Usually, the usage of a high-frequency transformer in microinverter provides galvanic isolation and eliminates the leakage current which flows from the PV panel to the ground. Therefore, in terms of maximum power point tracking (MPPT) performance, output current quality and the requirement of multi-function, the two-stage microinverter is more attractive and appropriate for the situation of higher requirements. Flyback converter cascaded with an unfolder circuit is commonly used for single-stage microinverter application, and it has the advantage of higher converter efficiency due to the simple structure and elimination of the power losses in the inverter stage, but a large DC input capacitor is needed to balance the double-line-frequency power ripple and it requires more challenging control techniques to meet the grid current regulation standards. The microinverters are usually classified into single-stage and two-stage topologies. Therefore, microinverter is considered to be the trend of future PV generation and attracts more and more attention recently. Microinverter, the so-called AC module, which integrates the grid-tied inverter with each PV panel and provides an effective solution for the mismatch and partial shading of PV panel, and it can achieve high conversion efficiency, plug and play operation, ease of expandability and low installation cost. Photovoltaic energy has become one of the most popular renewable energy nowadays and is widely applied in home, commercial and industrial applications. With the depletion of traditional fossil fuels and the problem of global warming, the distributed generation (DG) which is mainly composed of renewable energy generation is gaining more and more attention. IET Generation, Transmission & Distribution.IET Electrical Systems in Transportation.IET Cyber-Physical Systems: Theory & Applications.IET Collaborative Intelligent Manufacturing.CAAI Transactions on Intelligence Technology.
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