This paper presents a new supervisory control system (SCS) designed to maintain the power balance and obtain economic benefit by selling energy to the grid in a microgrid based on Z-source converters (ZSCs) with renewable energy, energy storage systems (ESSs), and charging station for electric vehicles (EV) connected to a medium voltage direct current (MVDC) link. The main components of the microgrid are a photovoltaic (PV) system, battery (BAT) and green hydrogen system with a fuel cell (FC), electrolyzer (LZ) and hydrogen tank as ESSs, a local grid connection and two units of fast chargers for EVs. Owing to the proposed configuration, the output voltages of the components can be adapted to the MVDC to control their output power and reduce the number of power converters compared to the common configuration without ZSCs. Thus, the configuration by itself and the SCS can be considered the main novelties of this paper. The simulation results and the hardware-in-the-loop tests show that the proposed system (ZSC-based configuration and SCS) is perfectly valid for the microgrid, and confirm the proper operation of the SCS to achieve an economic benefit from the use of the grid.

This paper presents an energy management system (EMS) based on a novel approach using model predictive control (MPC) for the optimized operation of power sources in a hybrid charging station for electric vehicles (EVs). The hybrid charging station is composed of a photovoltaic (PV) system, a battery, a complete hydrogen system based on a fuel cell (FC), electrolyzer (EZ), and tank as an energy storage system (ESS), grid connection, and six fast charging units, all of which are connected to a common MVDC bus through Z-source converters (ZSC). The MPC-based EMS is designed to control the power flow among the energy sources of the hybrid charging station and reduce the utilization costs of the ESS and the dependency on the grid. The viability of the EMS was proved under a long-term simulation of 25 years in Simulink, using real data for the sun irradiance and a European load profile for EVs. Furthermore, this EMS is compared with a simpler alternative that is used as a benchmark, which pursues the same objectives, although using a states-based strategy. The results prove the suitability of the EMS, achieving a lower utilization cost (−25.3%), a notable reduction in grid use (−60% approximately) and an improvement in efficiency.