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

This paper explores the stability of non-synchronous hybrid ac/dc power grids under the hybrid angle control strategy. We formulate detailed 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 and 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. Further, we conclude the almost global asymptotic stability of the hybrid ac/dc power grids under the hybrid angle control. Last, we present a numerical verification of the theoretical results.