Management of a PEM Electrolyzer in Hybrid Renewable Energy Systems - Fuzzy Modeling and Control: Theory and Applications - page 219

Fig. 12.9 OPC server, simulink and rule viewer running in the same PC
Figure 12.10 shows the most representative of involved variables for the sys-
tem operation during 20th February 2012 from 10:00 to 17:00. In Fig. 12.10 athe
irradiation and the hydrogen production are plotted.
In Fig. 12.10 b the evolution of the controller output, Vfuzzy, is shownwith the cur-
rent consumption of the electrolyzer. Figure 12.10 c depicts the battery SOC variation
and the electrolyzer current. As can be seen, whereas the electrolyzer is producing
hydrogen, the battery SOC is still growing because the PV modules provide current
for both demands.
Figure 12.11 shows data corresponding to 23rd March 2012 from 10:00 to 13:30,
illustrating the operation of the system during a cloudy day.
As can be seen in Fig. 12.11 a, the hydrogen production follows the variations
of the incident irradiance, so such production adapts to the power availability. In
Fig. 12.11 b, the effects of the clouds on the output signal of the FLC, Vfuzzy, and
the corresponding change in the electrolyzer current are shown.
Figure 12.11 c shows a similar situation to that of 20th February 2012, the battery
SOC is increasing at the same time that hydrogen is being generated due to the current
delivered by the PV modules.
The results under real operating conditions constitute a proof-of-concept of the
validity of the proposed control structure to adjust the control signal to the power
availability.