Research on DC Dynamic Model Equivalent Theory and Equivalent Platform

The increase of DC load such as electric vehicle charging data center accelerates the promotion of DC distribution network. However, the operation performance of DC grid has changed greatly comparing with traditional AC system. Physical dynamic simulation is a method to establish a model similar to the actual system according to the similarity principle. This simulation method should ensure that the process in the model is similar to the process in the actual system, and has the same physical essence. Traditional equivalent was based on electromechanical transient which cannot be applied to the DC system because of the power electronic control. The current research mainly focuses on the dynamic model method and theoretical research of DC transmission network, and lacks systematic discussion on the equivalence principle of DC distribution network. Aiming at the problem of the lack of dynamic equivalence theory and methods for DC distribution systems, this paper proposes a coherent equivalence theory suitable for AC/DC converter topology, gives an equivalence criterion for DC power systems, and constructs a direct flow model equivalence experiment platform to verify the effectiveness of the dynamic model system.