A Series-Parallel Multiport Flexible Interconnection Topology for AC/DC Distribution Networks

The use of flexible interconnection technology enhances the power stability in medium-voltage (MV) distribution grids with a high proportion of renewable energy and new loads. It can effectively regulate the power flow of the interconnected distribution grids with a fast response time. This paper presents a novel series-parallel power flow control topology flexibly interconnecting a single DC port with multiple AC ports. The DC port provides an additional control degree of freedom, allowing independent control of the active power and reactive power at each AC port. The proposed topology features high modularity and enables easy expansion of the AC ports connected adding only a small number of devices. The operation principle, control strategy, and parameter design of the proposed topology are systematically presented. The feasibility of the proposed topology has been validated based on the PSCAD/EMTDC offline simulation model and the real-time digital simulator (RTDS) experiment model.