Grid-Coupled Dynamic Response of Battery-Driven Voltage Source Converters

With the increasing interest in converter-fed is-landed microgrids, particularly for resilience, it is becoming more critical to understand the dynamical behavior of these systems. This paper takes a holistic view of grid-forming converters and considers control approaches for both modeling and regulating the DC-link voltage when the DC-source is a battery energy storage system. We are specifically interested in understanding the performance of these controllers, subject to large load changes, for decreasing values of the DC-side capacitance. We consider a fourth, second, and zero-order model of the battery; and establish that the zero-order model captures the dynamics of interest for the timescales of the examined disturbances. Additionally, we adapt a grid search for optimizing the controller parameters of the DC/DC controller and show how the inclusion of AC-side measurements into the DC/DC controller can improve its dynamic performance by predicting the evolution of the DC-side dynamics. This improvement in performance allows for a reduction in transient voltage deviations across the DC-link capacitor and, consequently, potentially reducing the risk of premature failure.