# Variable Multiple Interleaved Bi-Directional DC/DC Converter with Current Ripple Optimization
## 5 The Experiment and Results  
### Experimental Platform  
The experimental platform is shown in Figure 17, it can be divided into a control module, power module, output module, power supply, and programmable load. The TMS320F28377 microcontroller is used to control the whole system, and the XC3S500E-PQ208 is used to generate the PWM signal with the specific phase shift angle. The PWM signal is transmitted to the power module through the optical fiber. In the experiment, the 30 V bus voltage is generated by the DC stabilized power supply, the load capacitance C is replaced by a programmable load, the switching frequency is set to 10 KHz, the value of filter inductance is 3 mH, the output current is 6 A. The Experimental Results of the Current Ripple Optimization in Variable Channel Interleaving Bidirectional DC/DC Power Converter  
The current ripples of the 6 A output current of the DC-DC converter are shown in Figure 18. Figure 18a-1 represents the current ripples which are corresponding to different multiplicities in parallel when the duty cycles are 0.25, 0.33, 0.4, and 0.5, respectively. As can be seen in Figure 18a-c, when the duty cycle is 0.25, the maximum current ripples are 80 mA, 100 mA, and 120 mA when the number of parallel multiplicities is 4, 5, and 6, respectively. As can be seen in Figure 18d-\(f\), when the duty cycle is 0.33, the maximum current ripples are 160 mA, 145 mA, and 65 mA, when the number of parallel multiplicities is 4, 5, and 6, respectively. As can be seen in Figure 18g-y, when the duty cycle is 0.4, the maximum current ripples are 200 mA, 90 mA, and 100 mA, when the number of parallel multiplicities is 4, 5, and 6, respectively. As can be seen in Figure 18j-l, when the duty cycle is 0.5, the maximum current ripples are 130 mA, 140 mA, and 120 mA when the number of parallel multiplicities is 4, 5, and 6, respectively. All optimization results of current ripples under different duty cycles and parallel multiplicities in Figure 18 are identical to not only the simulation results above but also the analytical results in Table 1, which demonstrate that the optimization method proposed in this paper is precise and practical. The three pictures of the same line in Figure 18 clearly show the size of the current ripple under a different number of parallel channels with the same duty cycle. By extracting the data in Figure 18, Table 3 can be obtained. Compared with Figure 18, Table 3 is more intuitive and convincing in numerical representation. Table 3 intuitively illustrates the number of parallel branches that should be taken to minimize the current ripple under experimental conditions. Figure 17: Experimental platform. In order to simplify the analysis process, only the current ripples corresponding to duty cycles 0.25 and 0.5 are adopted. Figure 19a-f shows the current ripples of the first three channels when the parallel multiplicity is 4, 5, and 6. It can be seen that the larger the \begin{table}
\begin{tabular}{c c c c c} \hline \hline \multirow{2}{*}{**Duty Cycles**} & \multicolumn{2}{c}{**The Maximum Current Ripple of the Number of \(N\) Multiple Parallel Channels/mA**} & \multicolumn{2}{c}{**The Number of Parallel**} \\ \cline{2-4}  & \(N=4\) & \(N=5\) & \(N=6\) & **Channels to Be Used** \\ \hline
0.25 & 80 & 100 & 120 & 4 \\
0.33 & 160 & 145 & 65 & 6 \\
0.40 & 200 & 90 & 100 & 5 \\
0.50 & 130 & 140 & 120 & 6 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Output current ripples of DC-DC converter with different duty cycles under the same output current. Figure 18: Output current ripples of DC-DC converter with different duty cycles under the same output current.