## 5 Simulation Results
### Comparison with Some Other Sliding Surfaces
During the simulation, the load resistance \(R\) is suddenly decreased from the nominal value of 20 \(\Omega\) to 10 \(\Omega\) at time \(t=0.045\) s and then back again at time \(t=0.12\) s. Figure 12 illustrates the dynamic reactions of the output voltage and output current to a rapid change in load resistance when \(V_{ref}=48\) V. Accordingly, during the step transition,  
Figure 9: The motion of state variables on the proposed surface and \(S_{2}\). the output current smoothly increases, and then it returns to its initial value once the step transition happens again. These modifications result in the output voltage undershoot and overshoot of roughly 10.5% at \(t=0.045\) s and \(t=0.12\) s, respectively. The recommended SMC approach absorbs voltage variations in both cases within 18 ms. As can be observed from (11), load resistance also has an effect on the switching frequency, similarly to input voltage. This effect is plotted in Figure 13. The switching frequency varies significantly in the open loop during the load variations that take place during the times depicted in the linked graph and deviates greatly from the reference value. In contrast to the open loop, the same figure illustrates how T2 FS exhibits a highly robust dynamic response to load variation at \(t=0.045\) s. The disturbance that takes place at \(t=0.12\) s has slightly affected the switching frequency, but the proposed IT2 FS dampened this variation in approximately 50 ms.  
**Test-3:** In the final test, the performances of both proposed control schemes are evaluated in response to changes in the reference value of the output voltage. The outcomes of the dynamic responses are shown in Figure 14. First, the reference voltage is decreased from 48 to 40 V at time \(t=0.045\) s and then back again at time \(t=0.12\) s. With a satisfactory dynamic response, the SMC tracks the changes in the reference trajectory at \(t=0.045\) and  
\[S_{2}=\lambda_{1}\Big{(}V_{ref}-V_{0}\Big{)}+\gamma_{1}\Big{(}I_{ref}-I_{L} \Big{)} \tag{13}\]0 Open-loop and closed-loop control of switching frequency under start-up and input voltage disturbance. \[S_{2}=\lambda_{1}\Big{(}V_{ref}-V_{0}\Big{)}+\gamma_{1}\Big{(}I_{ref}-I_{L} \Big{)} \tag{13}\]1 The dynamic response of SMC in the output voltage under an input voltage step change. \(t=0.12\). Additionally, the results show that the proposed approach can regulate the output voltage in a steady state both before and after the step changes. As for \(f_{s}\), its behavior under this test is shown in \[S_{2}=\lambda_{1}\Big{(}V_{ref}-V_{0}\Big{)}+\gamma_{1}\Big{(}I_{ref}-I_{L} \Big{)} \tag{13}\]2 The switching frequency exhibits a significant fluctuating behavior when left uncontrolled. Furthermore, in this case, it is much more oscillating compared to its controlled state. On the other hand, as can be seen from the same figure, the proposed IT2 FS adequately maintains the switching frequency on the reference orbit in the steady state. Furthermore, the undershoot- and overshoot-caused reference voltage value has been eliminated in the proposed IT2 FS. \[S_{2}=\lambda_{1}\Big{(}V_{ref}-V_{0}\Big{)}+\gamma_{1}\Big{(}I_{ref}-I_{L} \Big{)} \tag{13}\]3 Transient response of recommended SMC in output voltage under load resistance step changes. \[S_{2}=\lambda_{1}\Big{(}V_{ref}-V_{0}\Big{)}+\gamma_{1}\Big{(}I_{ref}-I_{L} \Big{)} \tag{13}\]4 Transient response of switching frequency under load resistance step changes.