Search

Virtual synchronous generator (VSG) has been a grid-friendly integration control technique for the integration of grid-connected inverters. However, the emulated inertia and damping of VSG control technique can also be used in the field of dc systems. In this article, a virtual synchronous control is proposed to dampen the wideband oscillation of dc voltage in a dc microgrid. The proposed control strategy contributes to maintaining the synchronous operation of dc converter with the network. Besides, the relationships among damping, inertia, wideband oscillation, rate of change of voltage (RoCoV) as well as DC voltage nadir (DCVN) are studied. It is concluded that the RoCoV and DCVN are similar as the oscillation frequency and fluctuation ranges of poorly-damped oscillation, respectively. A unified concept is proposed by connecting the oscillation-related stability with the inertial transient response originated from the imbalanced powers/mismatched currents. Besides this, the inertia plays the same role as damping because the inertia contributes to maintaining the original state and damping to impeding further change. A new feedback analytical method is proposed to clarify the important role of RoCoV and DCVN on the motion of dc voltage. Finally, the theoretical results are compared with simulations and experiments. [ABSTRACT FROM AUTHOR]

• This article proposes virtual inertia and virtual damping based output impedance amplitude compensation control strategy to dampen oscillation of DC-side voltage. • The proposed virtual inertia control provide a amplitude compensation of output impedance, and damping the fluctuation of DC voltage caused by interaction between DC converter and the remaining networks of the DC microgrid. Voltage is prone to oscillation in a DC microgrid because of interaction between the power converter and the remaining parts of the networks. For this issue, this paper develops an impedance modeling based on linearization method for stability analysis. It is found that the wideband oscillation is prone to occurring concluded from stability analysis. Furthermore, the impact of parameters on stability of the microgrid is studied. Besides, a new closed-loop control model is proposed based on the DC current control loop. It is found that the current loop includes a peak which may impact the voltage oscillations. It is because voltages are interacted with the currents. Based on this idea, a new amplitude compensation control strategy based on virtual inertia emulation is proposed to dampen oscillation of the voltages by shaping the amplitude of output impedance. And theoretical analysis show good feasibility of the proposed control. Finally, the proposed conceives are demonstrated by experiments. [ABSTRACT FROM AUTHOR]

• This article proposes a VSM control strategy to dampen oscillation of DC-side voltage, and to improve damping performance and inertia for DC power system. • This paper proposed a new modeling method for identifying the dynamic interactions between multiple converters in a DC microgrid. DC system is characterized by low inertia and weak damping, which leads to a couple of stability issues. This paper proposes a modeling method for analyzing the DC-side oscillations occurred in DC microgrid with taking multi-paralleled converters into account. A new modeling is developed for analysis of dynamic interaction between multiple power converters. Thus, it is found that dynamic interaction between multiple converters will result in the poorly-damped oscillation of DC voltage. Besides, the poorly-damped modes will aggravate the stability of DC system. To cope with this issue, a virtual synchronous machine (VSM) control approach is proposed to suppress the oscillation of DC voltage, strengthen inertia, and improve damping performance of DC microgrid. Besides, the controller tuning of the VSM has a large flexibility that it does not depend on the system parameters. Finally, the proposed conceives are demonstrated by simulations. [ABSTRACT FROM AUTHOR]