Differential Single-Phase Inverters With Active Power Decoupling: A Survey

This paper provides an overview of differential single-phase inverter topologies with active power decoupling (APD) and their main control techniques. Owing to the advantage of achieving APD without additional semiconductor devices, thus boosting inverter reliability at a minimum cost, these topologies have gained increasing interest, especially for small-scale photovoltaic applications. Therefore, in this study, we consider it essential to synthesize the main differential single-phase inverters, their operating principles, and provide a unified mathematical description for each topology. The study identified and analyzed three main structures: buck, boost, buck–boost, and derived topologies. First, a comparative analysis, including a hardware assessment in terms of the DC-link voltage requirements, voltage and current stresses on the switches, and losses, shows the performance of various inverter topologies under different operating parameters (e.g., input voltage and decoupling capacitance). Second, this paper discusses the main control strategies applied to this class of inverters to achieve both primary control (autonomous or grid-connected operation) and APD functions, while highlighting the development of control algorithms that are less dependent on parameter variations and more robust to external disturbances. Finally, the need for further research on reliability improvement in single-phase differential inverters, particularly in the context of emerging technologies, such as high-speed switches (e.g., wide-bandgap semiconductors) and advanced control techniques, is emphasized.