## 4 Experimental Verification of the Proposed Integration Method  
To verify the above simulation analysis, a fully integrated LCCL-S structure prototype was developed, as shown in Figure 9. The design specifications and circuit parameters of the magnetic coupling structure are shown in Table 1. Among them, \(L_{p}\), \(L_{s}\), and \(L_{in}\) were wounded by EUW Litz wire. More precisely, the thickness of the ferrite bar used is 5 mm to prevent saturation and excessive core loss. Additionally, the dimensions of the coils, ferrites, aluminum plates, and air gap in the experiment are the same as the simulation conditions. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Variable** & **Selected Value** & **Variable** & **Selected Value** \\ \hline \(L_{p}\) & 81.31 uH & \(f_{o}\) & 85 kHz \\ \(L_{s}\) & 43.83 uH & Air gap & 100 mm \\ \(L_{in}\) & 20.01 uH & Main coupling coefficient \(K_{p-s}\) & 0.2018 \\ \(C_{s}\) & 80.28 nF & DC input voltage & 380 V \\ \(C_{p}\) & 167.22 nF & Output power & 3.3 kW \\ \(C_{f}\) & 59.03 nF & Load resistance & 14.62 \(\Omega\) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Essential parameters of the proposed system. Figure 8: Self-inductance value changes in the extended DD coil at different distances between \(D_{1}\) and \(D_{2}\). Figure 9: (**a**) Experimental prototype, (**b**) receiver coil, and (**c**) transmitter coil and two kinds of compensation inductor structures. First, when the compensation inductor is the DD coil and extended DD coil, the \(K_{p-s}\), \(K_{in-s}\), and \(K_{in-p}\) of the magnetic coupling structure are measured, respectively, and compared with the simulation results, as shown in Table 2. Since the simulated and measured values of \(K_{in-p}\) are close to 0 for the system in the aligned and misaligned state, they are not shown in Table 2. In particular, the measured results show that the \(K_{p-s}\) and \(K_{in-s}\) values are slightly different from the simulated values because any slight manipulation of the coil during the measurement process may affect the result, but the error is small and acceptable for the experiment. Next, the proposed system is misaligned by 100 mm in the \(X\)-axis direction, adopting the DD coil as the compensation inductor, and the \(K_{in-s}\) of the magnetic coupling structure is 0.0125. However, when the extended DD coil is adopted as the compensation inductor, \(K_{in-s}\) is 0.0843 and still 0.0622 at a misalignment of 150 mm, resulting in relatively better second magnetic coupling, further verifying the simulation results. Moreover, comparing the inductance values of the DD coil and extended DD coil with the same number of turns, the DD coil inductance value is 0.56 \(\upmu\)H higher than the extended DD coil because of the increased distance between the two small unipolar coils between the extended DD coil. Therefore, the extended DD coil has a slightly increased number of turns, which is the same as the inductance value of the DD coil. Furthermore, two groups of comparative experiments are performed under the condition that the system is well-aligned. Precisely, the input voltage of the system is 380 V, and the DC power supply is connected to the full-bridge inverter and inverted into high-frequency AC power. Particularly, the inverter uses C3 MOO30090K with a high withstand voltage as the SIC MOSFETs. Since the waveforms, input voltage, and output power of the two groups of experiments are similar, only the experimental results of the extended DD coil are shown. Figure 10 shows that the IPT system realized the zero-voltage switching (ZVS) between the inverter current and output voltage, which facilitates a reduction in the switching loss of the inverter and improves efficiency. In addition, it can be seen from Figure 11 that the system output power can reach 3.3 kW with a DC-DC efficiency reaching 94.359% when the system is in an aligned state.