Resiliency Enhancement and Power Quality Optimization of Converter-Based Renewable Energy Microgrids

The converter-based renewable energy microgrids are becoming indispensable parts of power grids. Nevertheless, the increasing risks by different causes deteriorate the resiliency of their grid integration. In this article, a sensorless combined control method for the grid-connected converters is proposed to enhance the resiliency in different aspects and against multiple risks. Power quality improvement is also considered in the proposed method, along with enhancing resiliency. A single control system is proposed to deal with unbalanced grid conditions, severe load changes, and short circuit faults. The control system has a low dependence on the system parameters. Also, a new reference calculation is proposed to improve the system performance under balanced and unbalanced conditions. It provides stable operation under normal and abnormal conditions, such as unbalanced voltages, voltage sag, faults, etc. The operation under the proposed control system is compared with the one under a conventional control system to confirm its performance superiority through simulation and experimental results.