## 3 Results  
Figure 6 presents a simple scheme of a wireless power transfer (WPT) system that operates using resonant coupling between two inductive coils. The AC voltage source generates an alternating current which flows through a series RLC circuit. The resistor accounts for potential losses in the circuit, while the inductance stands for the transmitting coils and the capacitance is added to achieve resonance conditions at the pre-defined frequency. In the VC design, the secondary circuit is replicated for each vertical coil, five in the case presented in this work. For simplicity, Figure 6 displays only one secondary coil and the symbol denotes the coupling coefficient between the VC and the transmitter coils. The voltage induced in the secondary coil passes through another capacitor, which further tunes the receiving side to the same resonant frequency as the transmitter. This resonance allows for maximum power transfer efficiency between the coils. The alternating current induced in the receiving coil then enters a full-bridge rectifier, which converts the AC power from the coil into direct current (DC) to charge the EV battery via a DC capacitor link. To measure the efficiency, we calculate the power at both the transmitting and receiving sides of the system. We determined the power by using Equation (1) using the time-dependent voltage/current of the source or the receiving end:  
\[P=\frac{1}{T}\int_{0}^{T}V(t)\cdot I(t)\,dt \tag{1}\]  
The system's efficiency \(\eta\) is defined as the following ratio:  
\[\eta=\frac{P_{\text{receiver}}}{P_{\text{transmitting}}} \tag{2}\] \begin{table}
\begin{tabular}{l c c c c} \hline \hline  & **VC Large [cm]** & **VC Lab [cm]** & **DDQ Large [cm]** & **DDQ Lab [cm]** \\ \hline \multirow{3}{*}{**Transmitter**} & Outer: \(50\times 50\) & Outer: \(5\times 5\) & Outer: \(50\times 50\) & Outer: \(5\times 5\) \\  & Inner: \(36.4\times 36.4\) & Inner: \(4.8\times 4.8\) & Inner: \(36.4\times 36.4\) & Inner: \(4.8\times 4.8\) \\  & Thickness: 1 & Thickness: 0.4 & Thickness: 1 & Thickness: 0.4 \\ \hline \multirow{3}{*}{**Distance Between**} & \multirow{3}{*}{75} & \multirow{3}{*}{6} & \multirow{3}{*}{75} & \multirow{3}{*}{6} \\ \
\begin{tabular}{l} **Centers of** \\ **Transmitting Coils** \\ \end{tabular} & & & & \\ \hline \multirow{3}{*}{**Ferrie**} & \multirow{3}{*}{25} & D: Outer: \(38\times 50\) & D: Outer: \(3.8\times 5\) \\  & & & Inner: \(29\times 41\) & Inner: \(2.9\times 4.1\) \\  & & & Height: 1 & Height: 0.1 \\  & & Height: 0.2 & Q: Outer: \(50\times 50\) & Q: Outer: \(5\times 5\) \\  & & & Inner: \(41\times 41\) & Inner: \(3.95\times 3.95\) \\  & & & Height: 1 & Height: 0.1 \\ \hline \multirow{3}{*}{**Distance**} & \multirow{3}{*}{25} & \multirow{3}{*}{2} & DD: 0 & DD: 0 \\  & & & Q: on top of & Q: on top of \\  & & & DD coil center & DD coil center \\ \hline \multirow{3}{*}{**Distance Receivers**} & \multirow{3}{*}{30} & \multirow{3}{*}{3} & \multirow{3}{*}{30} & \multirow{3}{*}{3} \\
\begin{tabular}{l} **from Transmitting** \\ \end{tabular} & & & & \\ \hline \multirow{3}{*}{**Number of Turns**} & Transmitter: 11 & Transmitter: 11 & Transmitter: 11 \\  & Receiver: 10 & Receiver: 10 & D: 3.5 turns & D: 3.5 turns \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Dimensions of DDQ and VC simulated and lab models. When the receiver coils layout passes above the transmitter, the coupling allows for an efficient energy transfer. At resonance, the impedance is minimized; hence, the current is maximized and the induced voltage at the receiver end supports an optimized charging procedure of the battery. The proposed VC configuration includes one pair of transmitting coils and five receiving coils, resulting in a complex matrix of coupling interactions among the coils. This is because the coupling occurs not only between the transmitting coil and each receiving coil but also among the receiving coils themselves. Each coil is influenced by the magnetic fields generated by all other coils, leading to mutual-inductance effects across the entire system.