Energy storage systems (ESSs) allow improving the stability and efficiency of the electrical grids with a high penetration of renewable energy sources. Moreover, the use of Hybrid ESSs (HESSs) enables storage solutions with both high-energy and high-power densities, by combining different storage technologies such as diverse battery chemistries, ultracapacitors, or hydrogen fuel cells to name a few. In this article, an HESS-based multioutput multilevel (MOM) converter is presented. The proposed topology enables decoupled control of each ac converter voltage output. The internal switching states further allow the use of different storage units and high-quality multilevel voltage in each ac output. The mathematical model of the proposed topology and the defined operation region of the system, besides a model-predictive control strategy, are developed. Finally, simulation and experimental results validate the performance of the proposed topology.

Currently, more decoupled photovoltaic (PV) systems demonstrate significant advantages in terms of efficiency increasing the competitiveness of the produced energy. This trend has been performed specifically in string and multistring configurations, where DC-DC converters are used to perform more distributed maximum power point tracking (MPPT). However, high variability in PV sources requires wide input voltage range capacity for the DC-DC converter affecting the efficiency of a classical DC-DC converter topology. Serial partial power converters (S-PPC) have drawn the attention in the last years due to its high efficiency processing only a fraction of the total power. In this paper it is proposed a two-stage approach for high efficiency step-up/down performance for a partial power conversion. Compared with the Type 1 or Type 2 step-up/down S-PPC, the proposed converter can operates with wider range of operation and presents higher partiality over the full operating range, leading to a higher global efficiency. Simulations are provided to verify the validity of the proposed two stage approach.

This paper explores a novel three-port series-partial-power converter structure to enable electric vehicle (EV) fast chargers. Besides handling a fraction of the power being delivered to the battery, the converter provides both step up and step down of its output voltage, hence being able to interface legacy 400-V as well as state-of-the-art 800-V EVs. Compared to existing partial power converters with both buck and boost capability, the proposed three-port structure is shown to be able to operate over a wider range of operation. Simulation results show the effectivness of the proposed converter, reaching 98.65% maximum efficiency. The proposed topology is finally verified to be an interesting alternative for the dc-dc stages in EV charging stations.