Hydrogen based configurations for an overhead crane with quasi-Z-source inverter

Abstract

Most of the overhead cranes used to date are powered by diesel engine or electrical grid and voltage source inverter. The economic and environmental costs of fossil fuels, and the unsteady price of electricity, encourage exploring new applications for developing electric power technologies. In this scenario, the main objective of this paper is to analyze the technical and economic feasibility of two new configurations based on hydrogen system and quasi-Z-source inverter (qZSI) for an overhead crane. The first configuration uses a fuel cell (FC) connected to a qZSI to supply the crane. The second one integrates an electrolyzer (LZ) as an energy storage system (ESS) into the impedance network of the qZSI (without additional DC/DC converter), which allows to recover energy during the regenerative braking of the crane and use it to produce hydrogen. The modelling and control are described, and short simulations of the working cycle of the crane under different initial hydrogen tank levels, and long simulations with several working cycles, are considered. The results show the technical viability of the two hydrogen-based configurations and the control systems implemented, since they can power the crane under all the situations studied. Nevertheless, the configuration with FC and LZ presents a higher energy efficiency (65% vs 44% with the FC-only configuration). Regarding the economic study, both configurations are compared with a diesel-based and with a full-electric configuration powered by the grid. Analyzing both hydrogen-based configurations, the results show that the configuration with FC and FZ becomes more profitable after 1.56 years, despite the higher initial cost. However, both configurations result more expensive than those based on diesel engine and fully powered by the grid. The two proposed configurations would be more cost-effective than the initial configuration in a plausible future with a 40% decrease in hydrogen cost.