Comparative study on power decoupling technology based on double frequency disturbance suppression of single-phase photovoltaic inverter

Abstract

During the grid connection process, single-phase photovoltaic inverters frequently encounter the issue of instantaneous power imbalance between the AC and DC sides. This results in twice the line frequency disturbance power being transmitted to the DC side, severely affecting the system's stability and performance, especially maximum power point tracking efficiency. To address this problem, research in photovoltaic grid-connected technology is now focusing on power decoupling technology to suppress double-frequency disturbances, referred to as power decoupling. This article covers the three main approaches to power decoupling—passive, active, and composite—and focuses on analyzing the circuit topology of the latter two approaches applied to single-phase photovoltaic inverters. The advantages and disadvantages of different power decoupling circuit topologies are discussed in detail, and a comparison is made in this article. Detailed discussions on current power decoupling technology trends and potential future directions, as well as recommendations for further refining grid-connected PV technology, are provided.