Inertia emulation with incorporating the concept of virtual compounded DC machine and bidirectional DC–DC converter for DC microgrid in islanded mode

Abstract

Independence in energy generation, attention to environmental issues, limited fossil fuel sources, and easy access to renewable energy sources have led governments, industry, and engineering to use renewable energy sources for decades. Meanwhile, microgrids for residential, commercial, industrial, and military purposes are widely used using these resources. However, the use of these sources in microgrids is associated with the challenges of uncertainty and lack of inertia. Therefore, by using energy storage systems in DC microgrids, the mentioned challenges can be overcome by emulating inertia. The purpose of this paper is to present a virtual compounded DC machine (VCDCM). The governing equations of the compounded DC machine have been accurately studied and the desired characteristics of this machine have been used to emulate inertia through the control of the buck‐boost converter connected to the energy storage systems in the concept of VCDCM. Proposed scheme; in an islanded microgrid with maximum components and standards required; Simulated in the Simulink/MATLAB environment. The results obtained under different scenarios confirm the ability of the proposed scheme to stabilize the DC bus voltage. The magnitude of DC bus voltage deviation from the reference value when an error occurs has resulted in a significant reduction compared to conventional schemes.

Inertia emulation with the concept of virtual supercapacitor based on SOC for distributed storage systems in islanded DC microgrid

“…As shown in Figures 7 and 8, the proposed scheme meets this challenge with the correct exchange of power at load change moments. The proposed scheme, in addition to reducing voltage changes at power change moments, does not have the complexity of the scheme [16]. This factor simplifies the adjustment of control parameters.…”

“…Therefore, in [15], by simulating the simplest type of DC machine, inertia is provided to DCMG. By analysing the specifications of the compound dc machine in [16], the governing relationships of this machine are simulated. In addition to the many advantages of this proposed design, the use of the buck‐boost converter with normal efficiency, lack of electrical insulation and nonconsideration of the protective purposes of batteries can be named as factors that need further research.…”

Research on Virtual DC Generator-Based Control Strategy of DC Microgrid with Photovoltaic and Energy Storage

“…VDCG is applied to the converter of the load side to reduce bus voltage fluctuation caused by random disturbance of the load [13,14]. Furthermore, references [15][16][17][18][19] proposed a control strategy applying VDCG to the source-side converter of DC microgrid to effectively subdue the influence caused by power fluctuation. In references [15][16][17], the VDCG control method was implemented in the energy storage interface converter, changing the control structure to possess superior voltage dynamic performance and inertial support ability.…”

“…Furthermore, references [15][16][17][18][19] proposed a control strategy applying VDCG to the source-side converter of DC microgrid to effectively subdue the influence caused by power fluctuation. In references [15][16][17], the VDCG control method was implemented in the energy storage interface converter, changing the control structure to possess superior voltage dynamic performance and inertial support ability. However, the VDCG approach used in the PV interface converter [18,19] has inertia and damping characteristics due to adding the mechanical and electromagnetic equation of DC generator.…”