*5.1. Open Loop System Response*

While switching from CC mode to CV mode, *V<sup>o</sup>* voltage is 44 V and *I<sup>o</sup>* current is 2.5 A. At this point, the *R<sup>L</sup>* equivalent battery resistance is 17.6 Ω. The IPT system must operate in CC mode below the equivalent load, and in CV mode above it. The *R<sup>L</sup>* magnitudes to be used in the simulation were selected by considering the nominal values of the resistors used in the experimental study. Accordingly, *R<sup>L</sup>* was set to 8.5 Ω, 10.5 Ω, and 14 Ω, respectively, to examine the CC mode. In this mode, *V<sup>F</sup>* was kept constant at 60 V.

According to the experimental results, as the equivalent resistance increases, the load voltage *V<sup>o</sup>* also increases (Figure 7a). The load current *I<sup>o</sup>* is not affected by the load change as a general response of the SS topology (Figure 7b). *V<sup>o</sup>* and *I<sup>o</sup>* seen in the simulation results also coincide with the experimental results (Figure 7c,d). *Energies* **2022**, *15*, x FOR PEER REVIEW 10 of 16

The range of the change is 17.6–440 Ω in CV mode. As SOC increases, the equivalent will also increase too. In this case, the load power increases with the in‐ creasing output voltage. Therefore, the primary side current will increase. The for‐ ward voltage was set to 40 V in this section of the experiment in order to protect the cir‐ cuit elements. The load was increased from 16 Ω to 22 Ω, 28 Ω, and 32 Ω for the test in the CV section. As seen in Figure 8a, continues to increase. For s in the CV section, the simulation model gives close responses to the experimental results (Figure 8b). If the variation of is examined depending on , it is seen that the primary side current magnitude doubles its nominal value at 32 Ω, although a ி is applied below the nomi‐ nal operating voltage (Figure 8c). Considering that the equivalent resistance value will approach 440 Ω when the battery is fully charged, it is obvious that the primary side The range of the *R<sup>L</sup>* change is 17.6–440 Ω in CV mode. As SOC increases, the equivalent *R<sup>L</sup>* will also increase too. In this case, the load power increases with the increasing output voltage. Therefore, the primary side current *I<sup>P</sup>* will increase. The forward voltage was set to 40 V in this section of the experiment in order to protect the circuit elements. The load was increased from 16 Ω to 22 Ω, 28 Ω, and 32 Ω for the test in the CV section. As seen in Figure 8a, *V<sup>o</sup>* continues to increase. For *RL*s in the CV section, the simulation model gives close responses to the experimental results (Figure 8b). If the variation of *I<sup>P</sup>* is examined depending on *RL*, it is seen that the primary side current magnitude doubles its nominal value at 32 Ω, although a *V<sup>F</sup>* is applied below the nominal operating voltage (Figure 8c). Considering that the equivalent resistance value will approach 440 Ω when the battery is fully charged, it is obvious that the primary side current must be controlled.

current must be controlled.

(**a**) (**b**)

(**c**)

**Figure 8.** (**a**) measured ை; (**b**) simulated ை; (**c**) measured when is 16 Ω, 22 Ω, 28 Ω, and 32 Ω, respectively. **Figure 8.** (**a**) measured *VO*; (**b**) simulated *VO*; (**c**) measured *I<sup>P</sup>* when *R<sup>L</sup>* is 16 Ω, 22 Ω, 28 Ω, and 32 Ω, respectively.
