Decentralized $H_{\infty}$ Voltage Regulation for DC Microgrids Under Load Variations

Direct current (DC) microgrids have gained increasing attention as a promising architecture for reliable and efficient power distribution in renewable-based systems. Their ability to interface seamlessly with distributed generation (DG) units, energy storage, and electronic loads makes them ideal for modern power networks. However, ensuring stable bus voltage remains challenging under load variations, reference changes, and plug-and-play (PnP) operations. This paper proposes a decentralized$H_{\infty}$control strategy for robust voltage regulation in DC microgrids. A comprehensive state-space model of converterinterfaced DG units is developed and augmented with integral action to eliminate steady-state error. The controller gains are synthesized using Linear Matrix Inequalities (LMIs) to guarantee robust stability and bounded$H_{\infty}$performance against system uncertainties and external disturbances. Simulation studies conducted on a representative DC microgrid demonstrate that the proposed controller achieves faster transient response, smaller overshoot, and stronger disturbance rejection compared with a pole-placement design, validating its effectiveness for reliable and scalable voltage control in DC microgrids.