# Single-Switch Non-Isolated Resonant DC-DC Converter for Single-Input Dual-Output Applications
## 3 Model and Experimental Prototype
### Simulation Results  
The simulation conditions have been established to obtain two bipolar voltages of \(\pm 12\) V from an input voltage source (\(V_{g}\)) of 10 and 14 V. For the power switch, a MOSFET model was used. The trigger pulses are generated through a pulse generator designed to maintain the average value of the output voltage at \(\pm 12\) V. The switching frequency is set to 411 kHz when \(V_{g}\) is 10 V and to 541 kHz when \(V_{g}\) is 14 V, with \(L_{R}\) = 2.1 \(\mu\)H and \(C_{R}\) = 12 nF, which establishes an off-time of 900 ns. The values chosen for the rest of the passive components in the converter are: \(L_{1}\) = \(L_{2}\) = \(L_{3}\) = 220 \(\mu\)H, \(C_{1}\) = \(C_{2}\) = 1 \(\mu\)F and \(C^{+}_{o}\) = \(C^{-}_{o}\) = 330 \(\mu\)F.  
The ZVS-QR SEPIC-Cuk combination converter has been analyzed using a simulation model, first in step-down mode. The waveforms shown in Figure 7 correspond to a simulation with \(R_{Load_{1}}\) and \(R_{Load_{2}}\), first with 10 \(\Omega\) and then with 20 \(\Omega\) (where the resonant action is maintained in both cases with \(V_{g}\) = 14 V). This has allowed us to check the intervals' duration, the peak and average values of the resonant waveforms, the current and the voltage, provided by (2)-(6), for the specified load range and the following variables: voltage in the gate terminal (\(V_{Gate}\)), resonant inductor current (\(i_{L_{R}}\)), resonant capacitor voltage (\(v_{C_{R}}\)), resonant inductor voltage (\(v_{L_{R}}\)), resonant capacitor current (\(i_{C_{R}}\)), freewheel diodes voltage (\(V_{D_{1}}\) and \(V_{D_{2}}\)) and current through the MOSFET (\(i_{Q}\)). In the same way, the results shown in Figure 8 correspond to \(V_{g}\) = 14 V, \(R_{Load_{1}}\) and \(R_{Load_{2}}\) of 10 \(\Omega\), but with a change in the switching frequency from 411 kHz to 200 kHz at 0.075 s. In this case, due to the change in frequency, the output voltages vary between \(\pm 11.8\) and \(\pm 22.7\) V, and there is a change in the converter operation from step-down to step-up mode. In addition, the results shown in Figure 9 also correspond to \(V_{g}\) = 14 V, with a switching frequency of 411 kHz, but with a change in \(R_{Load_{1}}\) and \(R_{Load_{2}}\) from 20 \(\Omega\) to 10 \(\Omega\) also at 0.075 s. As a result, the output voltages vary between \(\pm 11.7\) and \(\pm 17\) V, and the converter also changes operating mode (from step-up to step-down), but now due to the change in the load. In the same way, the simulation results shown in Figure 10 correspond to the behavior of the combined converter in step-up mode, with \(R_{Load_{1}}\) and \(R_{Load_{2}}\) first of 10 \(\Omega\) and then 20 \(\Omega\) (where the resonant action is maintained in both cases) and \(V_{g}\) = 10 V. These results have made it possible to verify the performance of the ZVS-QR SEPIC-Cuk combination converter shown in Table 1. As it can be seen, all the waveforms agree with the analytical analysis, which has been shown in Figure 5. In addition, the conversion ratio is also satisfied quite accurately. Each waveform is analyzed with the analytically obtained values in order to verify the consistency of the proposed converter. \begin{table}
\begin{tabular}{c c} Input Voltage (\(V_{g}\)) & 10–14 V \\ Output Voltage (\(V_{o}\)\({}^{+}\), \(V_{o}\)\({}^{-}\)) & \(\pm 12\) V \\ Switching Frequency (\(f_{s}\)) & 550–180 kHz \\ Power & 30 W \\ Switch (\(Q\)) & IRFP1405 (65 V, 95 A, 5.3 m\(\Omega\)) \\ Freewheel Diodes (\(D_{1}\), \(D_{2}\)) & MBR360 (60 V, 3 A, 0.73 V at 3 A, 25 \({}^{\circ}\)C) \\ Filter Inductors (\(L_{1}\), \(L_{2}\), \(L_{3}\)) & 220 \(\mu\)H, 1.5 A \\ Link Capacitors (\(C_{1}\), \(C_{2}\)) & 1 \(\mu\)F, 16 V \\ Output Capacitors (\(C_{o}\)\({}^{+}\), \(C_{o}\)\({}^{-}\)) & 330 \(\mu\)F, 16 V \\ Resonant Inductor (\(L_{R}\)) & 2.1 \(\mu\)H \\ Resonant Capacitor (\(C_{R}\)) & 10 nF, 16 V \\ \end{tabular}
\end{table} 
Table 2: Specifications and Components Used for the SILO ZVS-QR SEPIC–Cuk Combination Converter.