**6. Experimental Analysis**

The performance of the proposed EMS is verified by the laboratory-scale DC microgrid. The output power of the PV and fuel cell are DC, but for output power is AC.Thus, the AC power is converted to DC with the help of converters. All three sources are integrated to a common DC bus, and a charge controller is used to maintain the voltage level. Two batteries are connected in parallel to supply the demand. One is the priority load battery, and the other is the commercial load battery. The charging and discharging modes of the batteries are based on the availability of power in the DC microgrid. The hardware description for the DC microgrid is presented in Table 5.



The common DC bus voltage of the laboratory scale system is 24 V, and the 24 V/220 V converter is used to maintain the voltage level at load bus. The EMS is tested under the following cases:


The EMS continuously monitors the load power with respect to the renewable power generation. Based on its performance, the DC microgrid will supply the load. Two types of loads are considered to validate the performance: one is the priority load, and the other is the commercial load.

The priority load is the lighting load that will charge during the day and discharge at night. The commercial battery is charged based on the availability of RES with respect to the load. The experimental results are shown in Table 6.

(1) Case 1: *P<sup>G</sup>* > *P<sup>L</sup>*

During 7 a.m.–8 a.m., the total power generated from the REG is 370 W. At that instant, the demand is 250 and the load current is 1.2 Amps. The excess power (120 W) is stored in the commercial load battery. The voltage of the DC bus and the load current waveform is shown in Figures 13 and 14.

$$\text{(2) Case 2: } P\_G = P\_L$$

When the load is raised at 9 a.m.–10 a.m. to generate power, the load power is 440 W and the load current is 2 A, and the generated power continuously supplies the load without any interruption. At that interval, the commercial battery is in standby mode (no charging and discharging). The load current and priority load battery charging waveform are shown in Figures 15 and 16.

(3) Case 3: *P<sup>G</sup>* < *P<sup>L</sup>*

Normally, PV does not supply power from 6 p.m.–6 a.m. due to the sun irradiation portfolio. During this time, the rest of power sources (wind and fuel cell) combine with battery to supply the load. At 8 p.m.–12 a.m., the load is considered to be 900 W and the available generation is 600 W. In this case, the microgrid power demand is satisfied through a combination of battery and available energy sources (wind and fuel cell). The load current, commercial load battery, and priority load battery charging waveform are shown in Figures 17 and 18. If the total generation on the microgrid is low when compared to the load, the diesel generator will switch on to supply the load until the renewable power becomes active. From all the three cases, this system will be reliable and supply the load without any interruption. The main advantage of this DC micro grid is that it will supply the load to the consumer with the depth penetration of renewable energy sources rather than the diesel generator. It is concluded that the prototype of the 500 W microgrid is tested and validated with different conditions. The results satisfy the EMS for both the simulation and the hardware setup. The DC microgrid architecture is scalable for 15 kW to satisfy the load demand in rural communities.


**Table 6.** Experimental results at different time periods.

**Figure 13.** Voltage across each renewable energy source.

**Figure 14.** Load current during 7 a.m.–8 a.m.

**Figure 15.** Load current during 9 a.m.–10 a.m.

**Figure 16.** Load current during 8 p.m.–12 a.m.

**Figure 17.** Commercial battery charging/discharging profile.

**Figure 18.** Priority load battery charging/discharging profile.
