# Analysis and Implementation of a Hybrid DC Converter with Wide Voltage Variation
## 5 Experimental Results
Figure 8: Measured results of the proposed converter under \(V_{in}\) = 60 V: (**a**) load current, load voltage, and input voltage under a constant current or constant voltage control; (**b**) the gate voltages of \(S_{1}\)–\(S_{4}\) under \(V_{o}\) = 40 V; (**c**) \(v_{S1,g}\), \(v_{S1,ee}\), and \(i_{S1}\) under \(V_{o}\) = 40 V; (**d**) \(v_{ab}\), \(i_{L,1}\), and \(-v_{C,1}\) under \(V_{o}\) = 40 V; (**e**) \(i_{L,2}\) and \(-v_{C,2}\) under \(V_{o}\) = 40 V; (**f**) the gate voltages of \(S_{1}\)–\(S_{4}\) under \(V_{o}\) = 52 V; (**g**) \(v_{S1,ge}\), \(v_{S1,ee}\), and \(i_{S1}\) under \(V_{o}\) = 52 V; (**h**) \(v_{ab}\), \(i_{L,1}\); and \(-v_{C,1}\) under \(V_{o}\) = 52 V; (**i**) \(i_{L,2}\) and \(-v_{C,2}\) under \(V_{o}\) = 52 V.  
Figure 9: \(Cont.\)  
Figure 10 gives the test results of the converter under \(V_{in}\) = 238 V and the maximum power conditions. The half-bridge resonant circuit and half-wave diode rectifier are used in the converter (Figure 1c) under \(V_{in}\) = 238 V input. Only switches \(S_{1}\) and \(S_{2}\) are controlled on the left-hand side. Figure 10a gives the gate voltages and resonant current and voltage on the input side. The resonant current and voltage on the output side are provided in Figure 10b. The switch voltage and current of \(S_{1}\) are provided in Figure 10c. The switching frequency of the converter at \(V_{in}\) = 238 V input and full power condition is about 96 kHz, which is close to the resonant frequency (100 kHz). The resonant currents \(i_{Lr,1}\) and \(i_{Lr,2}\) are quasi-sinusoidal waveforms. Power switch \(S_{1}\) is also turned on at zero-voltage switching under the \(V_{in}\) = 238 V condition (Figure 10c). Figure 10: Measured results of the proposed converter under \(V_{in}\) = 238 V, \(V_{o}\) = 52 V, and \(I_{o}\) = 7.8 A: (**a**) \(v_{S1,g}\), \(v_{S2,g}\), \(i_{Lr,1}\), and \(\
eg_{C,1}\); (**b**) \(i_{Lr,2}\) and \(\
eg_{C,2}\); (**c**) \(v_{S1,g}\), \(v_{S1,ee}\), and \(i_{S1}\). Figure 11 provides the experimental waveforms under \(V_{in}\) = 480 V and the maximum power conditions. The half-bridge resonant circuit and full-wave diode rectifier are used on the left-hanf side and right-hand side of the converter (Figure 1d) under the \(V_{in}\) = 480 V input. The waveforms \(v_{S1,g}\), \(v_{S2,g}\), \(i_{Lr,1}\), and \(-v_{Cr,1}\) are given in Figure 11a. The waveforms \(i_{Lr,2}\) and \(-v_{Cr,2}\) are provided in Figure 11b. The waveforms \(v_{S1,g}\), \(v_{S1,ce}\), and \(i_{S1}\) are shown in Figure 11c. The switching frequency of the converter at the \(V_{in}\) = 480 V input and maximum power condition is about 114 kHz. From the test results in Figure 11c, \(S_{1}\) is also turned on at zero-voltage switching under \(V_{in}\) = 480 V. For the backward power flow operation (from \(V_{o}\) to \(V_{in}\)), \(V_{o}\) = 52 V and \(V_{in}\) is controlled at 400 V. Therefore, \(S_{5}\)-\(S_{8}\) are controlled on the right-hand side and the half-wave diode rectifier is operated on the left-hand side (Figure 1e). Figure 12 provides the experimental results under the backward power flow condition. Figure 12a shows the experimental waveforms \(v_{S5,g}\)-\(v_{S8,g}\) and the resonant currents and voltages are provided in Figure 12b. Figure 12c gives the test results of the switch current and voltage of \(S_{5}\). From the test results in Figure 12, the proposed converter can achieve reverse power flow operation well and switch \(S_{5}\) on the right-hand side can turn on at zero-voltage switching. The measured circuit efficiencies of the converter are 87.1%, 90.3%, 92.8%, and 93.6% at the \(V_{in}\) = 60 V, 118 V, 238 V, and 480 V inputs and maximum power conditions.