Flexible Test Bench for Hybrid Battery-Supercapacitor Energy Storage Systems Based on Bidirectional Interleaved Half-Bridge Converters

Abstract

The increasing penetration of photovoltaic (PV) generation in low-and medium-voltage DC systems requires energy storage solutions capable of simultaneously ensuring fast power balancing and long-term energy management. Hybrid Energy Storage Systems (HESS), combining batteries and supercapacitors, represent a promising approach to address these requirements by decoupling power and energy functions. The effectiveness of HESS architectures strongly depends on the bidirectional power converters interfacing each storage element with the DC bus and on the associated control and energy management strategies. This paper presents the assessment of bidirectional DC-DC power converters within a flexible test bench oriented to PV-based hybrid storage systems, developed in the framework of the MetSuperCap European project. The activity focuses on the definition, modeling, and simulation-based validation of a laboratory-scale DC microgrid integrating a PV source, a battery system, and a supercapacitor bank. Detailed simulations are carried out in the PLECS environment to evaluate converter dynamics, DC-bus regulation, and power sharing under representative PV operating conditions. Experimental tests are then performed on a two-phase interleaved prototype operating in both buck and boost modes. The results confirm the bidirectional operation of the SC interface, the correct current sharing between the converter phases, and the expected ripple reduction due to interleaving under a 2 kW power reference and a total current limit of ± 50 A. The remaining development steps concern the extension of the experimental campaign to the maximum power operating range and the integration of the dedicated measurement chain required for traceable validation of the SC model.