Novel dynamic equivalent circuit model of integrated energy systems

With the transformation from individual energy systems to integrated energy systems (IES), equivalent circuit IES modeling is developed to represent the heat and electricity consistently for coordinated analysis, control and optimization. However, physical properties of equivalent parameters are a mismatch, and the key operation characteristics, including dynamics and coupling, have not yet been fully described, remaining obstacles for optimal electricity-heat coordination. In this study, a novel IES equivalent circuit modeling methodology is proposed. From the perspective of physical characteristics, the similarity of heat transfer and micro conductivity processes is determined. A novel thermoelectric equivalent rule with matched energy units is proposed, showing the corresponding relations of the basic state, power, and energy quantities between electricity and heat. Then, the equivalent rule is applied in IES equivalent circuit modeling, where the equivalent heat element models are established to characterize the electrothermal coupling and dynamics of heat subsystems. Finally, following the IES system structure, the IES equivalent circuit model is completed. A numerical comparison is performed to verify the effectiveness of the model. The simulation results demonstrate that the proposed model can fully capture the dynamic and coupling characteristics of IES.