Implementation and Performance Analysis of Unified Virtual Oscillator Control in MMC

With increasing renewable penetration and declining grid strength, power electronic converters must ensure reliable operation under adverse conditions. This paper presents a unified control strategy that embeds nonlinear oscillator-based voltage synthesis into modular multilevel converters (MMCs) to enable robust grid-forming functionality. The unified Virtual Oscillator Control (uVOC) is integrated with circulating current suppression and voltage modulation coordination, enabling autonomous voltage regulation and fault-limited behavior without the use of phase-locked loops. Simulation results validate the proposed method under weak grid, disturbance, and islanded scenarios. Fault ride-through (FRT) capabilities are demonstrated in compliance with IEEE 1547 standards, confirming improved transient performance and system resilience.