Fuzzy logic-based water heating control methodology for the efficiency enhancement of hybrid PV–PEM electrolyser systems

Abstract

This paper deals with the efficiency enhancement of the hybrid Photovoltaic–Proton Exchange Membrane Electrolyser (PV–PEM ELS) system. The electrolyser water temperature has been controlled to improve its efficiency. The system consists of 59 kW PEM electrolyser supplied by a PV generator through a boost converter for H2 production. The PV panels were sized to 74 kW of Belfort region. The PV panel characteristics were experimentally validated. The effect of temperature and irradiance on the PV characteristics (output power, voltage and efficiency) is shown. The Maximum Power Point Tracking (MPPT) approach was proposed for maximizing the energy captured by the PV panels. The water heat transfer between both the PV panels and the PEM ELS using a water pump has been considered to provide the necessary temperature. Water heating inside the PEM ELS was controlled using Fuzzy Logic Control (FLC) technique. As the produced H2 flow is dependent on the input water heating, the instantaneous reference PEM ELS input water temperature was determined using FLC. The optimal input water temperature was determined in order to maximize H2 production considering the physical constraints, especially the temperature limitation to avoid the evaporation. Therefore, the water temperature was optimally controlled to its instantaneous reference value by the Proportional–Integral (PI) control. The produced H2 flow would expand if the input water was heated. The effectiveness of the proposed FLC methodology towards improving the hybrid PV–PEM ELS system efficiency was verified through the maximization of both the PEM ELS produced H2 flow and the PV captured energy.