## 6 Experimental Results  
In order to validate the proposed converter, an experimental integrated power system setup (500 W/30 V) was implemented. The system consists of the proposed converter system that interconnects a Li-ion battery, an SC, a programmable power supply that acts as a PV emulator, and a programmable electronic load that enables the generation of customized load transients. The control scheme is implemented on a control platform that consists of TMS320C6713 DSP performing the calculations and a ProASIC(r)3 FPGA custom board used for the A/D conversion of voltage and current measurements and PWM signal generation. The DSP sampling and the PWM carrier switching frequency are both set to 10 kHz. The complete setup is shown in Figure 12, with the corresponding specifications listed in Table 4.  
The response of the converter system is evaluated under step load power transient experiments. The first test evaluates the response of the system following a large constant power peak load, as shown in Figure 13. Initially, the load consumes a constant power of 160 W, which is slightly more than the PV available power which remains constant for the duration of this experiment. As the required power from the energy storage is small, this is provided by the battery, which discharges with a low current (1 A) that is assumed to be below its current limit, and consequently, the SC current is  
Figure 11: The control scheme of the proposed converter. Figure 13a. At (t = 38 s), a large step change in the load power was applied (\(p\) = 400 W), causing the required power delivered by the energy storage to be significantly increased. As a result, the discharging current of the battery, which is the main source of stored energy, raises, reaching its limit of 5 A. The control senses this and forces the SC to contribute and support the load power peak by increasing its current to 11 A. This causes the discharge of most of SC stored energy which is seen in the SC voltage drop from 50 V to 22 V at the end of the peak power load (t = 65 s), as can be seen in Figure 13b. This test confirms the capability of the converter to maintain the output voltage(Vo) regulated at the desired value (30 V) as well as active control of the power share between the battery and the SC under the large disturbance introduced by the load power peaks. It also validates the buck-boost capability of the proposed converter at the SC port, which allowed the voltage of the SC to be changed from the higher value (50 V) that is above the Vo to the lower value (22 V) and below the Vo (which increase the utilization of SC energy capacity as discussed in Section 2) whilst maintaining the full controllability of the converter. \begin{table}
\begin{tabular}{c c} \hline \hline
**Type/Name** & **Rating/Specifications** \\ \hline Battery module & 42 V/6 Ah based on Panasonic NCR18650B cell with V\({}_{\text{max}}\) = 42 V and V\({}_{\text{min}}\) = 25 V \\ \hline SC-module & 8 F/60 V based on AVX SCCW45B107 cell with V\({}_{\text{max}}\) = 60 V and V\({}_{\text{min}}\) = 15 V \\ \hline PV module emulator & \(\text{VPv}_{\text{MPP}}\) = (15 \(-\) 22.5) V, \(\text{IPv}_{\text{MPP}}\) = (6 \(-\) 9) A \\ \hline SC stage inductor (L1) & 120 \(\mu\)H \\ \hline Battery stage inductor (L2) & 240 \(\mu\)H \\ \hline PV module inductor (L3) & 120 \(\mu\)H \\ \hline DC-link capacitor (C\({}_{\text{O}}\)) & 2200 \(\mu\)F \\ \hline Switching frequency (Fs) & 10 kHz \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Specifications of the used components in the experimental setup. Figure 12: Experimental setup for validating the proposed converter. The second test evaluates the performance of the proposed converter during the charging mode under imposed changes in the load. The changing scenarios are shown in Fig. 13. The experimental results during peak power loading: (a) Battery, SC, and PV currents and bus power; (b) Battery, SC, and output voltages and output current.