## 4 Experimental Verification  
### The Proposed Hybrid IPT Charger's Parameter Design for CC/CV Modes  
After the load-specific characteristics of the proposed design method were verified (as described in Section 3), a design of the primary and secondary pads that satisfied the desired \(P_{L}\), \(V_{L}\), and \(I_{L}\) was crafted. The maximum voltage and maximum current are given in (17) and (18), and accordingly, the pad parameters were considered. As indicated by  
Figure 6: Output characteristics of the proposed topology under different loads. (22), (23), and (24), this had an impact on the ratio of the pad's mutual and magnetization inductances. Figure 7 shows the 3D geometry design of the LCT, and its detailed design parameters are listed in Table 2.  
Considering the voltage and current on the primary and secondary pads, the appropriate wire diameter and distance of insulation between wires were considered. The coupling factor is affected by the size of the pad, the winding design, the external and internal diameters of the winding, and the separation distance. In order to increase the coupling factor, ferrite was added to the primary coil. On the secondary side, the pad is only composed of coils to reduce weight. To validate the analysis, a prototype of the proposed topology and the conventional SS topology was constructed. The practical parameters employed for the prototype are presented in Tables 1 and 3. The gap between the primary pad and the secondary pad was 10 mm, which is closer than the normal separation distance of EVs, resulting in a relatively high \(k\) of 0.3. The operation frequency was 85 kHz. The duty cycle of the inverter operates at 0.5. When configuring the experimental environment, the primary capacitor of the SS topology with the conventional design method was modified to work in the ZVS region. \begin{table}
\begin{tabular}{c c} \hline \hline
**Parameters** & **Values** \\ \hline Air gap distance & 10 mm \\ Turns per coil & \(N_{p}\): 17, \(N_{s}\): 5 \\ Primary coil dimension & 180 mm \(\times\) 92 mm \(\times\) 3.1 mm (0.12 mm/500) \\ Primary ferrite plate dimension & 200 mm \(\times\) 50 mm \(\times\) 5 mm \\ Primary shield dimension & 244 mm \(\times\) 136 mm \(\times\) 2 mm \\ Secondary coil dimension & 180 mm \(\times\) 92 mm \(\times\) 3.1 mm (0.12 mm/500) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Designed dimensional parameters of LCT. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & \multicolumn{5}{c}{**Experimental Outputs**} \\ \hline \(P_{out}\) & Short & 400 & 300 & 200 & 100 & Open \\ \(V_{L}\) & Short & 23.46 & 28.25 & 30.01 & 30.81 & 35.1 \\ \(I_{L}\) & 24.15 & 17.75 & 10.56 & 6.67 & 3.27 & 0.02 \\ \(R_{L}\) & 0.5 & 1.3 & 2.7 & 4.5 & 9.4 & 2000 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Practical parameters of the SS topology with conventional design for comparison. Figure 7: Loosely coupled transformer 3D model. Owing to resonance caused by primary pad inductance, the primary capacitor value of the SS topology with the conventional design method was 60.4 nF. The SS topology with the conventional design method had minimum output power, and the output power increased proportionally with resistance value owing to the CC output characteristic. The load resistance region of the SS topology with the conventional design method was assumed to be from 0.4 \(\Omega\) to 0.8 \(\Omega\) as the efficiency and output characteristics must be compared in the same power range. The output current of the SS topology with the conventional design method was determined by the input voltage, primary pad inductance, and secondary pad inductance. To compare efficiency at the same output voltage and current, the operation frequency and duty cycle of the inverter must be controlled. Therefore, in this experiment, only the same duty, switching frequency, input voltage, and rated output power were compared.