A Universal Droop-based Control Strategy for Single-Phase Two-Stage PV Inverters

摘要

Droop control is widely used in distributed generators for relating their terminal parameters to power generation. These generators are usually assumed to have enough capacities for supplying the required power. This is however not always true, especially with renewable sources with no or insufficient storage. To deal with this issue, an improved droop-based control is proposed for single-phase two-stage PV inverters. With this method, the PV inverter can operate in either MPPT mode or dispatched power mode when connected to the grid. Also, this control method can be used for realizing the operational control in islanded mode without major control reconfiguration. Regardless of the operating mode, the dc-bus voltage can be well regulated even in the presence of PV power fluctuations due to solar irradiance variations in this study. Finally, the proposed droop-based control method is demonstrated through simulation and experimental results.