Control strategies for alkaline water electrolyzers: A survey

In recent times, renewable energy sources have gained significant popularity because of the dwindling reserves of fossil fuels and the significant environmental damage resulting from their use. Among the various renewable energy sources, hydrogen stands out as one of the most crucial technologies for the future. Hydrogen can be produced through several different methods, and electrolysis is among the most frequently used methods. This method employs electrical energy to decompose water into its constituent hydrogen and oxygen molecules. When this electrical energy is derived from renewable sources such as solar or wind, then green hydrogen is produced. Systems that use electrolysis to produce hydrogen are known as electrolyzers. One of the primary challenges in the electrolysis process is ensuring the purity of hydrogen; proper control of the levels and pressures of the gas tanks can improve this purity. Automatic control strategies are very important for regulating the levels and pressures of the oxygen and hydrogen tanks. Researchers have proposed various classical techniques for controller design to mitigate this issue. This study seeks to offer a comprehensive and up-to-date review of existing research on control methods for alkaline electrolyzers, which has attracted considerable attention in recent times. The findings of this review offer valuable insight for future studies aimed at developing new control strategies to enhance hydrogen purity.