## 4 Results
### Simulation-Based Results  
For the simulation analysis, an electrical circuit as depicted in Figure 2 is developed in the Simulink environment. The internal resistances of the switching transistors and diodes are set to 0.8 and 0.06 respectively. The forward voltages of the diodes are adjusted to 1 V. A load resistance of 100 \(\Omega\) is selected to adjust the switching current to a safe level with 160 V peak input. The internal resistance of the 1 mH intermediate inductor is ignored. The switching signals that are described in Section 2 for non-inverting, inverting, and zero states realization are employed to obtain simulation results for variable output voltage and frequency. The outputs of Figure 11a,b are simulated by using non-inverting and inverting states respectively. These operating states also ensure the variable frequency realization as they are illustrated in Figures 12 and 13 for low and high-frequency operation respectively. The outputs of Figure 12 depict the frequency regulation in ascending fashion. The regulation in the output frequency is ensured by inverting or non-inverting the positive and negative input voltage at the output according to the requirement. \begin{table}
\begin{tabular}{c c c} \hline \hline
**Specifications** & **Proposed Topology** & **Topology in [24]** \\ \hline Center tap transformer & no & yes \\ \hline Core saturation problem & no & yes \\ \hline Shoot-through problem & no & yes \\ \hline Core losses & no & yes \\ \hline Number of switching transistors & & \\ operated in any operating mode. & & \\ \hline Number of conducting diodes operated & & \\ in any operating mode. & & \\ \hline Maximum breakover voltage & & \\ \hline Switching or chopping voltage & & \\ \hline Switching losses & & \\ \hline Conduction losses & & \\ \hline Harmonic factor & 0 & 100\% \\ \hline Power factor & Unity & 0.707 Lagging \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparison of the proposed topology with the converter in [24]. In the same way, the depicted outputs of Figure 13a-c illustrate the frequency variation in ascending order with a step increase of 50 Hz. This sort of output is achieved by inverting and non-inverting the positive and negative input voltage at the output. In frequency regulation, there is no use of zero-state that eliminates the current interruption problem of the inductor. But to avoid the shoot-through issue especially for frequency boost operation, a small turn-off delay should be inserted into the switching signals that are employed to change the output state from non-inverting to inverting and vice versa. The zero-state is mandatory to regulate the voltage at the output. Normally, for the regulation of the output RMS voltage, the non-inverting and zero states are alternatively employed. Here the care should be ensured once the operating state at the output is changed from non-inverting or in some cases inverting to zero-state. Because, during this interval, the inductor current is going to be interrupted. Especially, this will be the case for high-frequency choppers. The voltage spikes in the output voltage that are opposite to the polarity of the input voltage are inductive voltage kicks. That may appear in the output voltage once the non-inverting or inverting operating state is switched to zero-state. Figure 11: Constant frequency (50 Hz) outputs during: (**a**) non-inverting state; (**b**) inverting state. Figure 12: Low-frequency outputs with respect to constant input frequency (50 Hz): (**a**) 50/4 Hz; (**b**) 50/3 Hz; (**c**) 50/2 Hz. The severity of these voltage kicks can be eliminated with the proper selection of the turn-off delay. Practically, these delays are inherently added due to the programming delays of the Arduino platform. This is not a serious issue for output voltage regulation with half-wave and full-wave controllers or on-off cycle controllers as non-inverting states end at zero input voltage or zero states start at zero input voltage.