Hybrid Angle Control and Almost Global Stability of Non-synchronous Hybrid AC/DC Power Grids

TL;DR

This paper analyzes the stability of hybrid AC/DC power grids with hybrid angle control, proving almost global asymptotic stability and providing conditions for stability and instability of equilibria.

Contribution

It introduces a comprehensive stability analysis framework for nonsynchronous hybrid AC/DC grids with hybrid angle control, establishing conditions for almost global stability.

Findings

Proved existence and uniqueness of system equilibria.

Demonstrated global attractivity and local stability of desired equilibrium.

Identified conditions leading to instability of other equilibria.

Abstract

This paper explores the stability of nonsynchronous hybrid ac/dc power grids under the grid-forming hybrid angle control strategy. We formulate dynamical models for the ac grids and transmission lines, interlinking converters, and dc generations and interconnections. Next, we establish the existence and uniqueness of the closed-loop equilibria for the overall system. Subsequently, we demonstrate global attractivity of the equilibria, local asymptotic stability of the desired equilibrium point, and instability and zero-Lebesgue-measure region of attraction for other equilibria. The theoretic results are derived under mild, parametric, and unified stability/instability conditions. Finally, relying on the intermediate results, we conclude the almost global asymptotic stability of the hybrid ac/dc power grids with interlinking converters that are equipped with hybrid angle control. Last, we present several remarks on the practical and theoretical aspects of the problem under investigation.