A DCDC converter for centralized energy storage in HVDC applications

Abstract

Energy storage systems (ESS) are often used to face grids stability problems, providing ancillary services. This paper introduces a modular converter to integrate a massive ESS built of supercapacitors to an HVDC link. This approach stores a big amount of energy in a single ESS, unlike other proposals that distribute the stored energy in series-connected submodules. The topology consists of two branches of half-bridge and full-bridge submodules. Due to the nature of the ESS, the converter must be able to handle with large voltage fluctuations on one side, from zero-voltage to full-charge (in the range of hundreds of kilovolts), and constant voltage on the other side (also in the range of hundreds of kilovolts). A control strategy is proposed, and simulations using average arm models demonstrate that the proposed converter satisfies the requirements, remaining stable and following the references as desired.

Douglas Lima Militao Pinheiro, Florian Errigo, Florent Morel.

Presented at IET PEMD 2024