8.2 The Proposed Hybrid System And Its Control Strategy Case Study
The simulation results of the PV/WT/PEMFC/battery hybrid system using ANN and fuzzy logic are discussed in this section. Simulation results are obtained by developing a detailed MATLAB/Simulink software package, as shown in Figure 8.5. Fig. 8.5 - Hybrid power system simulation model
The specifications of the renewable power sources used are given in Table 8.1
PV Sharp’s (NU-180) at (1kW/m2, 25o C) Wind turbine
Maximum power (Pm) 180 (W) Peak Output Power 3200 (W)
Open circuit voltage 30 (V) Base wind speed 11 (m/s)
Voltage at Pm 23.7 (V) Base rotational speed 520 (rad/s)
Short circuit current 8.37 (A)
Current at Pm 7.6 (A)
Table 8.1 - PV/WT system specifications
The specifications …show more content…
The power demand profile has a significant effect on determining the EMS. In this study, a practical load profile for two family members in resident application (Dursun & Kilic 2012) is established, as shown in Figure 8.6 (c). From this load profile it is evident that the average power demand is less than 2.4kW. The load profile during peak load periods (0 to 120 sec, 240 to 360 sec, and from 420 to 540 sec) varies from 3 to 4.5kW, as illustrated in Figure 8.6 (c). However, due to weather condition, the output power of the PV/WT system varies from 1.3 to 3.5kW, as shown in Figure 8.7. Therefore, a PEM fuel cell with a reversible ESS was added to the renewable power system. The battery bank system is capable of sustaining the extra load of 1.3kW for 1h during peak load demand periods. While, the PEMFC 6kW can meet the remaining extra power and protect the battery from …show more content…
8.7 (a) Total power of the solar power plant (b) Total power of the wind Turbine
Moreover, according to the proposed EMS algorithm, which shown in Section 7.4, battery SOC level is determining the operation of the PEM fuel cell, during peak load demand periods. Hence when the:
• SOC is low (≤ 40.5%), the remaining energy is satisfied by the PEMFC stack, and the extra power will be used to charge the battery (SOC goes high).
• SOC is high (≥ 80%), the remaining energy is satisfied by the battery bank only. At this time, the battery bank discharge current is very high and the battery bank terminal voltage drops significantly.
• SOC is between 40.5% and 80%, the remaining energy is satisfied by either the battery bank or by the hybrid PEMFC/battery system.
Therefore in the following subsections two cases have been tested during the simulation. The rated power of the PV/WT system is 6kW; the solar radiation, wind speed and user load profiles are the same for the three cases (Figure