Decentralized Cost-Based Dispatchable Virtual Oscillator Control for Grid-Forming Inverters

Decentralized power sharing among inverter-based distributed generators is a key pillar for maintaining stability and minimizing operational costs in islanded microgrids (MGs). Indeed, ensuring decentralized economic dispatch through cost-based droop control is common practice; however, it lacks inertial response, leading to significant frequency deviation and a high rate of frequency change during disturbances. This paper introduces an optimal sophisticated control algorithm based on an enhanced dispatchable virtual oscillator control (dVOC) framework for grid-forming (GFM) inverters. The proposed controller supports fully decentralized dispatch under nonlinear cost functions. Moreover, it incorporates negative derivative feedback into the outer loop, introducing an additional degree of freedom to improve overall stability by shifting the most dominant modes deeper into the left-hand side of the ω axis. Hence, with this aim, it acts as an optimal cost-driven dispatch controller during steady-state and transitions to a stabilizing inertia-emulating mode during disturbances, reducing frequency excursions and improving overall system stability. The proposed approach is evaluated through small-signal sensitivity analysis and detailed time-domain simulations, performed using MATLAB/Simulink. Furthermore, the proposed approach is validated experimentally and on a modified IEEE 38-bus system, which represents a scenario with a larger number of GFMs. Consequently, results demonstrate improved frequency regulation, robust performance under non-ideal conditions, and enhanced small-signal stability compared to conventional GFM control methods.