# Ferrites and Nanocrystalline Alloys Applied to DC-DC Converters for Renewable Energies
## 5 Experimental Results  
The values of the parameters for both MFT prototypes are obtained from the methodology presented in [16] and are listed in Table 9.  
The flux density obtained is higher in the nanocrystalline MFT, 0.8 T, than in the ferrite MFT, 0.2 T. This latter MFT has larger dimensions core and lower total power density. The total number of turns of the windings of the nanocrystalline MFT is 47.7% lower compared to the ferrite MFT. The nanocrystalline and ferrite cores are shown in Figure 8. The MFT prototypes are shown in Figure 9.  
Both MFTs are tested at 120 V/1 kVA/20 kHz with the typical square waves presented in the DC-DC converters, using a full H-Bridge converter. The equipment used is a DC variable source from 0 to 120 V, DSP, 12 V\({}_{\text{DC}}\) Source, MFT, load, and oscilloscope, as shown in Figure 10. In Figure 11, a block diagram is shown that represents the experimental configuration of Figure 10. Figures 12-14 show experimental results at 6%, 25%, and \begin{table}
\begin{tabular}{c c c} \hline \hline
**MFT** & **MFT with Ferrite Core** & **MFT with Nanocrystallyne Core** \\ \hline Number of phases & 1-phase & 1-phase \\ Core type & Toroidal (3C’90) & Toroidal (Vulterpem 500 F, W514) \\ Core dimensions & \(5.1\times 3.2\times 1.9\) cm & \(3\times 2\times 1.5\) cm \\ Number of turns of primary winding & 42 turns & 22 turns \\ Number of turns of secondary winding & 85 turns & 45 turns \\ Primary winding caliler & 13 AWG & 13 AWG \\ Secondary winding caliler & 16 AWG & 16 AWG \\ Flux density & 0.2 T & 0.8 T \\ Permeability & 3456 & 53,355 \\ \hline \hline \end{tabular}
\end{table} 
Table 9: Construction parameters of the MFTs. Figure 7: Input and output voltages and current for MFTs: (**a**) Nanocrystalline core, (**b**) ferrite core. \(50\%\) of the nominal power. The input and output voltages and currents resulted from experimentation with both MFTs are shown in Figure 15 at full load. Figure 8: Cores for the construction of both MFTs: **(left)**: Nanocrystalline, **(right)**: Ferrite. Figure 10: Laboratory prototype with a Full H-Bridge converter, MFT with Nanocrystalline core: **(a)** a DC variable source 0–120 V, **(b)** H Bridge (Mosfets), **(c)** DSP, **(d)** a 12V DC source, **(e)** MFT, **(f)** Load, and **(g)** Oscilloscope. Figure 9: MFTs prototypes featuring: a Nanocrystalline core (**left**), a ferrite core (**right**). The comparison between voltages and currents of both MFTs prototypes at full load (Figure 15) are presented in Table 10, along with the corresponding efficiency values. Table 11 shows the efficiencies obtained at 6%, 25%, and 50% of the nominal power. Figure 16 shows a thermography of the MFT prototype, taken with a thermal camera (Milwaukee M12 TM 7.8 KP). In this case, the maximum temperature was 73.7 \({}^{\circ}\)C for ferrite, and 46.4 \({}^{\circ}\)C for nanocrystalline alloys. The test was realized at 28 \({}^{\circ}\)C room temperature for 1 h.  
Figure 11: Block diagram of the experimental setup: (**a**) a DC variable source 0–120 V, (**b**) H Bridge (Mosfets), (**c**) DSP, (**d**) a 12V DC source, (**e**) MFT, (**f**) Load, and (**g**) Oscilloscope. Figure 12: MFT input and output voltages and currents (6% P\({}_{\text{nom}}\)): (**a**) Nanocrystalline, (**b**) Ferrrite. Figure 13: MFT input and output voltages and currents (25% P\({}_{\text{nom}}\)): (**a**) Nanocrystalline, (**b**) Ferrrite. The high efficiency of the nanocrystalline MFT is 99.8%, and 97.9% of the ferrite MFT. The other two parameters of great interest are the power density and the construction cost of each MFT. A comparison of these parameters is shown in Table 12. \begin{table}
\begin{tabular}{c c c} \hline \hline
**MFT** & **MFT with Ferrite Core** & **MFT with Nanocrystallyne Core** \\ \hline \(V_{in}\) & 119 V & 120 V \\ \(V_{o}\) & 247 V & 245 V \\ \(I_{in}\) & 7.95 A & 7.44 A \\ \(I_{o}\) & 3.75 A & 3.64 A \\ Efficiency & 97.9\% & 99.8\% \\ \hline \hline \end{tabular}
\end{table} 
Table 10: Input and output voltages and currents, and efficiency obtained at full load.