A Modified Adaptive Droop Control for Improved Load Sharing in Microgrids Considering DG Boundary Limits

The focus of the paper is on addressing a crucial aspect of microgrid operation, namely the need for efficient load sharing. In microgrids that employ high angle droop control, achieving optimal load sharing can be challenging and can potentially lead to instability. To overcome this issue, the paper proposes a modified adaptive droop control technique that stabilizes the system while ensuring appropriate load sharing. The technique involves controlling each distributed generator converter separately using high angle droop gains and a droop approach that predicts grid characteristics such as voltage, frequency, and impedance angle and magnitude. Active and reactive power can be injected into the grid separately, and a suitable dynamic can be introduced independent of the grid impedance's magnitude and phase. This ensures that the system remains stable and performs optimally, even under varying load conditions. Furthermore, during the load sharing process, the DG units have the potential to reach their maximum limits, which can lead to the collapse of the microgrid. To address this issue, a control strategy is introduced in this paper to alleviate the overloading experienced by the microgrid's units. The proposed modified adaptive droop control loop was tested on a microgrid test system, and simulation results demonstrate the effectiveness of the technique in achieving optimal load sharing while maintaining system stability. Overall, the paper provides valuable insights into the design and implementation of control strategies for microgrids, which can enhance their performance and reliability.