Frequency stability improvements based on automatic adjustment of synchronous power controller parameters

Abstract

This paper presents an automatic parameter adjustment technique for synchronous power controllers (SPC) in order to improve the dynamic frequency stability of the low inertia power systems. The proposed control method is based on a novel transfer function in which various grid and converter controller parameters involved in the stability studies have been thoroughly included. As the main contribution of this paper, the eigenvalue trajectory of the proposed transfer function has been determined, considering the variations of both virtual inertia and damping control parameters simultaneously. Furthermore, any corresponding operating point on this eigenvalue trajectory can be specified based on the desired frequency response characteristics of the system. Therefore, the inertia and damping coefficients of the converter controller can be simultaneously adjusted through the proposed controller algorithm as the second contribution of this paper. Also, as another novelty of this paper, it is demonstrated through analytical and theoretical studies that both damping ratio and natural frequency characteristics of a dynamic frequency response have profound effects on the controller parameter value adjustments. Simulation results have been employed in MATLAB/Simulink to confirm the performance of the proposed controller regarding the appropriate parameter value adjustments, development of the desired dynamic frequency responses, and the prominent interactions between the frequency response characteristics and the converter controller parameters.