Synchronized Resilience for Islanded Microgrids: A New Robust Virtual Oscillator-based Approach

This work proposes a new robust Hopf oscillator to enhance robustness and synchronization of N-parallel three-phase inverters in islanded Microgrids. The existing Hopf oscillator (HO) allows the inverter to operate in both grid-connected and islanded modes. However, the existing control strategy exhibits limitations, such as poor scalability and sensitivity to synchronization, especially in multi-inverter systems and islanded modes. This work proposes modification of the existing HO using sliding mode control (SMC) to enhance its robustness against disturbances and parametric uncertainties in an island Microgrid. The enhanced design ensures consistent synchronization under persistent disturbances and coordinated control of parallel inverters under varying system conditions. In addition, an additional controller is incorporated to ensure that the total harmonic distortion (THD) remains low in the presence of grid harmonic distortion, grid impedance variation, and filter parameter drift. The implementation of these two distinct control mechanisms guarantees smooth operation and improves the resilience of islanded Microgrids against disturbances. The simulation results show the efficacy of the proposed strategy to achieve robust synchronization, higher stability margins, and superior performance in contrast to the standard control techniques that are often implemented.