Design of Multiport Converters for Distribution Grids: Sizing, Topologies, and Control for Low and Medium Voltage Applications
Abstract
The escalating penetration of distributed energy resources (DERs) presents significant operational challenges to low-voltage (LV) and medium-voltage (MV) distribution networks (DNs), particularly in terms of voltage stability and bidirectional power management. Multiport converters (MPCs) are an efficient, unified solution to aggregate diverse resources and enhance system resilience. This article proposes a multistage design of MPCs. An optimization-based methodology is presented for optimally sizing the MPC terminals, minimizing total economic cost while simultaneously optimizing technical indicators such as annual line losses and voltage stability. This methodology is validated across two distinct utility use cases: a four-terminal MPC in an LV network, which successfully integrates photovoltaic (PV) generation and EV charging, and a two-terminal MPC in an MV network thateffectively mitigates voltage imbalances between parallel feeders. Furthermore, the work reviews suitable MPC topologies for these grid applications and proposes a qualitative comparison technique implemented in a MV application. Finally, some control architectures for the proposed topologies are thoroughly verified through control hardware-in-the-loop (CHIL) and experimental converter prototype testing.