A Resilient Grid-Forming Framework for Modular Parallel Converters Using Dynamic Coordination and Virtual Impedance Control

Traditional strategies for the parallel operation of AC inverters in power supply applications often lack fault management and sectorization capabilities, reducing the system’s resilience and modularity. Common parallelization methods include droop control, which avoids critical communication links but is sensitive to line and load parameters, and master–slave architectures, which offer better control capabilities but rely entirely on a single master unit. Additionally, conventional master–slave schemes do not support dynamic role reassignment without interrupting operation. This paper proposes a master–slave control strategy that enables autonomous role reassignment among inverter units in the event of master failure, without requiring system shutdown. The architecture achieves N+1 redundancy and provides all units with grid-forming capability. Role transitions are coordinated through a promotion–degradation mechanism over low-bandwidth communication buses such as CAN. The proposed approach ensures seamless role changes via local AC voltage reference generation, enhancing system robustness and continuity under fault conditions.