*5.2. Closed Loop System Response*

*5.2. Closed Loop System Response* Switched load magnitudes were selected as 12.8 Ω, 17 Ω, 22.6 Ω, and 32 Ω to observe the overall system response in CC and CV modes. The output voltage of the forward converter was fixed at 60 V for the system that passed the test section of the algorithm (Figure 9a). It was shown before in Figure 7b that did not change due to the SS to‐ pology effect in resistance changes up to 14 Ω. Therefore, a single resistance level of 12.8 Ω was considered sufficient to show the charge in CC mode in this section. The charging Switched load magnitudes were selected as 12.8 Ω, 17 Ω, 22.6 Ω, and 32 Ω to observe the overall system response in CC and CV modes. The output voltage of the forward converter was fixed at 60 V for the system that passed the test section of the algorithm (Figure 9a). It was shown before in Figure 7b that *I<sup>o</sup>* did not change due to the SS topology effect in resistance changes up to 14 Ω. Therefore, a single resistance level of 12.8 Ω was considered sufficient to show the charge in CC mode in this section. The charging took place in CC mode in the first part of the control algorithm.

took place in CC mode in the first part of the control algorithm. When the resistance increases from 12.8 Ω to 17 Ω, the output voltage *V<sup>O</sup>* increases (Figure 9b). In this case, since the forward current will tend to increase rapidly, the voltage *V<sup>F</sup>* is decreased by the control algorithm. However, a slight decrease was observed in *IO*. While the resistance is 22.6 Ω, the charge continues in the CV section. *I<sup>O</sup>* decreases with the increase in SOC (Figure 9c). The output voltage was kept constant by reducing *VF*. When the resistance was increased from 22.6 Ω to 32 Ω, *V<sup>O</sup>* was kept constant, and the *I<sup>O</sup>* charging current continued to be decreased. If the resistance magnitude continued to increase at this stage of the charge, it would continue to be throttled until *V<sup>F</sup>* was equal to *VF*\_*test*.

(**c**)

**Figure 9.** Experimental results of the control algorithm: the change of (**a**) ி; (**b**) ை; (**c**) ை. **Figure 9.** Experimental results of the control algorithm: the change of (**a**) *VF*; (**b**) *VO*; (**c**) *IO*.

When the resistance increases from 12.8 Ω to 17 Ω, the output voltage ை increases (Figure 9b). In this case, since the forward current will tend to increase rapidly, the volt‐ age ி is decreased by the control algorithm. However, a slight decrease was observed in ை. While the resistance is 22.6 Ω, the charge continues in the CV section. ை decreases with the increase in SOC (Figure 9c). The output voltage was kept constant by reducing ி. When the resistance was increased from 22.6 Ω to 32 Ω, ை was kept constant, and In the experimental results, there is an overshoot in the *V<sup>o</sup>* waveform and an oscillation in the *I<sup>o</sup>* waveform due to the sudden change in the load level. In the actual battery charge, these fluctuations will not be in question since there is not be such a sudden change in the equivalent resistance of the battery according to the SOC. In fact, these sudden changes can in practice be caused by a sudden change in the mutual inductance due to the occurrence of misalignment during charging or an object entering between the coil pads. These situations can be identified by detecting high-amplitude inrush current changes.

the ை charging current continued to be decreased. If the resistance magnitude continued to increase at this stage of the charge, it would continue to be throttled until ி was equal to ி\_௧௦௧. In the experimental results, there is an overshoot in the waveform and an oscil‐ lation in the waveform due to the sudden change in the load level. In the actual bat‐ tery charge, these fluctuations will not be in question since there is not be such a sudden change in the equivalent resistance of the battery according to the SOC. In fact, these The primary side should be protected by reducing the forward converter output voltage, if the secondary side is open-circuit at any stage of the charge. The load resistance was increased from 30 Ohm to 440 Ohm for observing this situation in the LTspice model. The variation of *V<sup>F</sup>* with the change of the resistance in the forward converter is shown in Figure 10. The *V<sup>F</sup>* voltage is reduced to 4.041 V. At this moment, *I<sup>F</sup>* also reaches the maximum allowable value. The variation of the current passing through the inductance *L<sup>F</sup>* in the forward converter with the switching of the load is shown in Figure 10b.

sudden changes can in practice be caused by a sudden change in the mutual inductance due to the occurrence of misalignment during charging or an object entering between the coil pads. These situations can be identified by detecting high‐amplitude inrush current

The primary side should be protected by reducing the forward converter output voltage, if the secondary side is open‐circuit at any stage of the charge. The load re‐ sistance was increased from 30 Ohm to 440 Ohm for observing this situation in the LTspice model. The variation of ி with the change of the resistance in the forward converter is shown in Figure 10. The ி voltage is reduced to 4.041 V. At this moment, ி also reaches the maximum allowable value. The variation of the current passing through

changes.

**Figure 10.** (**a**) ி; (**b**) the current of ி when disconnecting from the load. **Figure 10.** (**a**) *VF*; (**b**) the current of *L<sup>F</sup>* when disconnecting from the load.

The wireless charging system for the e‐bike developed in this paper was compared with the same power level IPTs in terms of efficiency. As can be seen in Table 3, the IPT proposed in this study provides the desired power transmission with higher efficiency at a higher transmission distance than its counterparts. Moreover, since the DC‐link voltage on the primary side is high, it can be directly connected to the AC grid. The wireless charging system for the e-bike developed in this paper was compared with the same power level IPTs in terms of efficiency. As can be seen in Table 3, the IPT proposed in this study provides the desired power transmission with higher efficiency at a higher transmission distance than its counterparts. Moreover, since the DC-link voltage on the primary side is high, it can be directly connected to the AC grid.

the inductance ி in the forward converter with the switching of the load is shown in


