Impedance modeling, dynamic analysis and damping enhancement for DC microgrid with multiple types of loads

Abstract The dc microgrid with multiple types of loads is considered to be a promising solution for integration of distributed generations (DGs). This paper presents the small signal impedance modeling of dc microgrid with multiple types of loads (including resistive loads, constant power loads and induction motor loads) which consists of source-side output impedance model and load-side input impedance model. Afterward, the Nyquist criteria based stability analysis is performed on the deduced small signal impedance models to investigate the interaction influence of different load states on the damping performance and stability boundaries of the dc microgrid system. Besides, a damping enhancement control strategy for dc microgrid is proposed in this paper based on the dual virtual inductive impedances. Since the dual inductive impedance can perform high-frequency attenuation feature during transients or oscillations, enhanced damping performance of the dc microgrid system is presented with the proposed control. Theoretical analysis and simulation cases show the validity and effectiveness of the proposed control strategy.