## 6 Experimental Results
Figure 16: Experimental waveforms of **(a)** the PFC stage (V\({}_{\text{Link}}\), V\({}_{\text{AN}}\), I\({}_{\text{A}}\), I\({}_{\text{BI}}\)) and **(b)** the DC/DC stage (V\({}_{\text{P}}\), I\({}_{\text{P}}\), V\({}_{\text{S}}\), I\({}_{\text{S}}\)) obtained by control of the constant output voltage (V\({}_{\text{o}}\): 400 V\({}_{\text{DC}}\)) in conditions of wind generator voltage V\({}_{\text{LL}}\): 249.3 V\({}_{\text{rms}}\) and load P\({}_{\text{O}}\): 1000 W.  
Figure 15: Experimental waveforms of **(a)** the PFC stage (V\({}_{\text{Link}}\), V\({}_{\text{AN}}\), I\({}_{\text{A}}\), I\({}_{\text{BI}}\)) and **(b)** the DC/DC stage (V\({}_{\text{P}}\), I\({}_{\text{P}}\), V\({}_{\text{S}}\), I\({}_{\text{S}}\)) obtained by control of the constant output voltage (V\({}_{\text{o}}\): 400 V\({}_{\text{DC}}\)) in conditions of wind generator voltage V\({}_{\text{LL}}\): 167.9 V\({}_{\text{rms}}\) and load P\({}_{\text{O}}\): 478 W.  
Therefore, the average link voltage (V\({}_{\rm Link}\): 565 V\({}_{\rm DC}\)) was selected through the experimental results obtained from Figure 17. Figures 18-20 show the operation of the link voltage (V\({}_{\rm Link}\): 565 V\({}_{\rm DC}\)) control by sensing only the primary-side link voltage (V\({}_{\rm Link}\)) without wireless communication. Also, the figures provide waveforms of the boost inductor current (I\({}_{\rm B1}\)), phase voltage (V\({}_{\rm AN}\)), phase current (I\({}_{\rm A}\)), link voltage (V\({}_{\rm Link}\)), and the primary-side terminal voltage/current (V\({}_{\rm P}\)/I\({}_{\rm P}\)) and secondary-side terminal voltage/current (V\({}_{\rm S}\)/I\({}_{\rm S}\)) of the DC-DC stage of the three-phase single-stage AC-DC converter under varying load conditions from a light load of 150 W to the rated load of 1 kW. The experimental waveforms reveal that, for the S-S compensation circuit, the primary-side square wave voltage (V\({}_{\rm P}\)) and current waveforms (I\({}_{\rm P}\)) show that the resonance current (I\({}_{\rm P}\)), which is delayed relative to the square wave voltage (V\({}_{\rm P}\)) at the a-b terminals, causes all primary-side switching devices to operate with zero-voltage switching (ZVS). Furthermore, Figure 21 presents an enlarged view of the boost inductor current (I\({}_{\rm B1}\)) waveform under a 478 W load condition. Figure 21a shows the boost inductor current (I\({}_{\rm B1}\)) waveform with two slopes in the interval \(0<\omega t\leq\Phi_{\rm cr,a}\), while Figure 21b depicts the waveform with three slopes in the interval \(\Phi_{\rm cr,a}<\omega t\leq\pi/2\). Therefore, as detailed in Section 2.2, the boost inductor current (I\({}_{\rm B1}\)) waveform demonstrates that the waveform exhibits two and three slopes in the intervals \(0<\omega t\leq\pi/2\), corresponding to the difference between the phase voltage (V\({}_{\rm AN}\)) and the link voltage (V\({}_{\rm Link}\)). Figure 17: Link voltage (V\({}_{\rm Link}\)) characteristics according to the load variation of the 3-phase single-stage AC-DC converter for IPT-based wind power generation system in the output voltage control (V\({}_{\rm o}\): 400 V\({}_{\rm DC}\)) through Bluetooth communication. Figure 18: Experimental waveforms of (**a**) the PFC stage (V\({}_{\rm Link}\), V\({}_{\rm AN}\), I\({}_{\rm A}\), I\({}_{\rm B1}\)) and (**b**) the DC/DC stage (V\({}_{\rm P}\), I\({}_{\rm P}\), V\({}_{\rm S}\), I\({}_{\rm S}\)) obtained by control of the constant link voltage (V\({}_{\rm o}\): 565 V\({}_{\rm DC}\)) in conditions of wind generator voltage V\({}_{\rm LL}\): 110 V\({}_{\rm rms}\) and load P\({}_{\rm O}\): 150 W.  
Figure 22 presents the total harmonic distortion (THD\({}_{\text{i}}\)), power factor (PF), and overall efficiency characteristics of the experimental results obtained by selecting the average link voltage (V\({}_{\text{Link}}\): 565 V\({}_{\text{DC}}\)) from the results shown in Figure 17 while controlling only the primary-side link voltage (V\({}_{\text{Link}}\): 565 V\({}_{\text{DC}}\)) without wireless communication.