Enhanced control of voltage source converters considering virtual inertia theory

Abstract

This article presents an enhanced control strategy for voltage source converters (VSCs) based on virtual inertia concept. Considering the significant share of renewable-based generations, frequency stability is noted as one of the most significant challenges of modern low-inertia power systems. Therefore, as the first contribution of this article, dynamic equations of the converter are utilized in order to study its proficient active and reactive power compensation capabilities. Then, this effective power factor correction of the proposed VSC is improved by adding inertia emulation characteristics in order to provide a more synchronous generator (SG) like behavior, which is beneficial from the frequency stability point of view. In addition to that, the impacts of changes in the main control parameters such as inertia and damping on dynamic performance are analyzed using the root locus method. This applied eigenvalue analysis has then been used to support a proper selection of parameter values, which is considered as another novelty of this article. In this regard, the designed algorithm providing auto adjustment capability of controller parameters based on a desired frequency response characteristic can improve the dynamic frequency stability of the system. The functionality of the proposed controller is validated through state-space analysis and simulations with MATLAB/Simulink. The superior performance of the proposed algorithm demonstrated through simulation results confirms that the proposed control method can be considered as a simple yet effective solution for the challenges of a reduced inertia power system.