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Green hydrogen has presented a prominent position in the current global energy transition framework because it has the potential to be used as a feedstock, a fuel or a carrier and storage of clean energy to balance electricity supply and demand. However, a Life Cycle Assessment (LCA) of green hydrogen is needed in order to measure the potential reductions in environmental impacts of large-scale implementation compared to existing technologies. Thus, this paper applies a systematic review with a bibliometric approach of studies on LCA applied to green hydrogen. The results show that studies on the subject are very current and present several practical applications, which are limited by data availability and information generalizations.

The modular multilevel converter (MMC) has been a subject of increasing interest for power electronics researchers, especially in HVDC applications. However, this paper considers the application scenario of a medium voltage distribution grid-connected MMC, using a model predictive control (MPC) with reduced number of states, as a control strategy to regulate the ac-side and circulating currents. In addition, an improved sorting algorithm is used to implement the task of maintaining the submodules capacitor voltages regulated, which results in a reduction of the average switching frequency. These control strategies are applied to a three-phase five-level MMC, and its performance is analyzed based on simulation results conducted in the environment of circuit simulations PSIM. Besides, an experiment was also carried out with a single-phase MMC prototype, and its results are presented, in order to prove the effectiveness of the control strategies proposed.