This document reviews fuel cell systems and their technologies, emphasizing the significance of renewable energy generation and the various types of fuel cells, including proton exchange membrane (PEMFC) and solid oxide fuel cells (SOFC). It discusses the challenges faced in commercialization, such as lifetime and cost, while highlighting ongoing advancements in fuel cell research and control algorithms for improving efficiency. Additionally, it addresses the role of power-conditioning units in integrating fuel cell systems with both standalone and grid-connected applications.