# Design of WPT System Based on Interleaved Boost Converter
## 5 Results and Discussion  
According to the previous theoretical analysis, this paper builds a 500 W wireless power transmission experimental prototype, as shown in Figure 10. The photograph of the experimental setup is as follows. The prototype is comprised of ten modules:  
1. a dc voltage source for the power circuit;
2. a dc voltage source for the driver and controller;
3. a boost inverter;
4. a primary compensation capacitor;
5. a transmitter;
6. a receiver;
7. a secondary compensation capacitor;
8. a full-bridge rectifier and a sampling circuit;
9. a resistive load;
10. two Bluetooth modules surrounded by yellow dashed circles. The electrical and physical parameters of the system are shown in Table 2.  
The voltage and current waveforms at each node of the system are shown in Figure 11 in the face-to-face situation. At this time, the output voltage is 100 V, the input power is 555 W, the output power is 500 W, and the system efficiency can reach 90.1%. At this time, the dead time of the interleaved boost converter is 0.37 us, the duty cycle is 0.5157, and the bus voltage is boosted to 206 V. When the primary and secondary sides are laterally offset by 200 mm, the output waveform is similar to that when the primary and secondary sides are aligned. At this time, the output voltage is 99.8 V, the input power is 578 W, the  
Figure 10: Photograph of the prototype. Figure 9: Changes of relative voltage gain \(G_{0}\) with primary and secondary side self-inductance before and after misalignment. **(a)** Alignment; **(b)** Offset to farthest distance. output power is 498 W, and the system efficiency can reach 86.2%. At this time, the dead time of the interleaved boost converter is 0.64 us, the duty cycle is 0.4728, and the bus voltage is boosted to 185 V. When the primary and secondary sides are offset by 100 mm longitudinally, the output waveform is similar to that when the primary and secondary sides are offset by 200 mm in the lateral direction. At this time, the output voltage is 100 V, the input power is 575 W, the output power is 500 W, and the system efficiency can reach 87%. At this time, the dead time of the interleaved boost converter is 0.67 us, the duty cycle is 0.4715, and the bus voltage is boosted to 183 V.  
Figure 12 shows the dynamic response waveform of the system. When the input voltage changes from 90 V to 120 V when the original and auxiliary sides are facing each other, the output voltage of the system remains unchanged, and the adjustment time is 62 ms. The dynamic performance of the system is excellent, which verifies the effectiveness of the closed-loop system. The experimental waveforms in different phase-shifted conditions are as shown in Figure 13. The duty cycle of parallel boost is 0.516, 0.473 and 0.471, respectively. As can be seen from the figure, ZVS is realized in different phase-shifted conditions. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Parameters** & **Value** & **Parameters** & **Value** \\ \hline Operation Frequency \(f_{0}\) & 85 kHz & Transmission Distance & 170 mm \\ Input Voltage \(U_{\text{in}}\) & 100 V & Lateral Offset Distance & 200 mm \\ Output Voltage \(U_{\text{O}}\) & 100 V & Vertical Offset Distance & 100 mm \\ Transmission Power \(P_{\text{N}}\) & 500 W & Rated Load \(R\) & 20 \(\Omega\) \\ Self-inductance of primary coil \(L_{\text{P}}\) & 1090.4 uH & Value of capacitor \(C_{1}\) & 3.215 nF \\ Self-inductance of secondary coil \(L_{\text{S}}\) & 258.9 uH & Value of capacitor \(C_{2}\) & 13.54 nF \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Main electrical and physical parameters of the prototype. Figure 11: The voltage and current waveforms at each node of the system in an aligned case. (**a**) DC/DC node; (**b**) AC/AC node. Figure 12: Changes of \(U_{\text{C2}}\) with primary and secondary side self-inductance before and after misalignment in experiment.