Hydrogen Production Efficiency Enhancement of Alkaline Water Electrolyzers Under Varying Temperature Via an Adaptive Multi-Mode Control

Abstract

Hydrogen production by water electrolysis is an ideal energy storage to smooth the power of renewable energy sources (RESs).  However, the low-load efficiency performance of alkaline water electrolyzers (AWEs) is poor so its operation range is limited, which makes it unfeasible to follow the fluctuant power of RESs. Besides, the power fluctuation will lead to the electrolyzer temperature variation. The temperature cannot maintain at a certain level and the efficiency performance is negatively influenced. Focusing on these problems, an efficiency enhancement control strategy for AWEs operating under varying temperature is introduced in this paper. First, the efficiency model of industrial AWEs is established based on the operating principle of AWEs. Then, a multi-mode adaptive control strategy is proposed to improve the hydrogen production efficiency of temperature-varying electrolyzers. Based on the U-I curves and Lagrange interpolation, parameter identification method is used to obtain the key parameters of the proposed efficiency model. Finally, the feasibility of the control strategy is experimentally validated on a 10kW industrial electrolyzer. The experimental outcome shows that by applying the proposed control strategy, the electrolyzer efficiency is raised from 21.54% to 42.73% under 15% of rated load at .The low-load hydrogen production efficiency of AWEs can be improved under different temperatures.

Keywords: hydrogen, efficiency enhancement, adaptive control, Parameter identification