Robust Stability Control Theory and Characteristics Analysis of Networked Energy Storage Converters under Large Disturbance Scenarios

Abstract

INTRODUCTION: Grid-Forming Energy Storage Converter (GFM-ESC) is a key interface equipment for the coordinated regulation of source and network in new power systems. However, the dynamic coupling mechanism between its multi-topology structures such as direct-mounted, string-type, and centralized types and large disturbance scenarios (new energy power fluctuations, power grid transient shocks) has not yet been clarified.

OBJECTIVES: Existing robust control methods do not embed topological feature constraints and are difficult to ensure the system stability margin under large disturbances under multi-topology. This theoretical gap limits the scene adaptability of GFM-ESC. In response to the above scientific issues, this paper focuses on Robust Stability Control Theory and Characteristics Analysis of Networked Energy Storage Converters under Large Disturbance Scenarios.

METHODS: First, a large disturbance dynamic model of multi-topology GFM-ESC was established. By analyzing the mapping relationship among wiring topology, component parameters and system state matrix, the energy flow mechanism and eigenvalue trajectory instability inducements of GFM-ESC under different topologies were revealed during large disturbances, and the influence of topological parameters on the system was quantified. Secondly, grounded on H∞ robust control theory, a robust stable control method for topology adaptation was proposed, a closed-loop control law embedded with topological features was derived, and Lyapunov stability theory was used to prove the robust convergence of this control method under large disturbances and topological parameter perturbation scenarios. Finally, through small signal analysis and large disturbance numerical simulation, the performance of the developed theory and method was verified.

RESULTS: Findings showed that the developed dynamic model can accurately describe the large disturbance characteristics of multi-topology GFM-ESC, and the corresponding robust control method can increase the system stability margin by 42%, and can still maintain the asymptotic stability of the closed-loop system when the topological parameters were perturbed by 15%.

CONCLUSION: The results of this study enhance the theoretical system for controlling large disturbances in the multi-topology GFM-ESC, providing a foundation for the collaborative design of GFM-ESC topologies in new power systems.