## 4 Experimental Results
As shown in Figure 9d, before S\({}_{2}\) is turned off, the auxiliary switch S\({}_{A1}\) is turned on and the auxiliary current \(i_{A1}\) increases rapidly from 0 A; thus, the auxiliary switch realizes zero-current turn-on. When S\({}_{2}\) is turned off, the auxiliary current \(i_{A1}\) reaches the maximum value. The voltage of the auxiliary capacitance \(C_{A1}\) is steady and the value of \(V_{CA1}\) is approximately 190 V, which is consistent with the theoretical calculation value. According to (5), to realize zero-voltage turn-on of the main switch, the minimum value of the auxiliary current \(i_{A\_peak\_min}\) should be 2.8 A. According  
Figure 9: Main experimental waveforms of the ITLDC: (**a**) turn on process of S\({}_{1}\) without ACACs, \(I_{0}\) = 2 A, (**b**) turn on process of S\({}_{1}\) without ACACs, \(I_{0}\) = 10 A, (**c**) turn-off process of S\({}_{1}\), (**d**) auxiliary current build-up process, (**e,f**) switching process of S\({}_{1}\) with ACACs, \(I_{0}\) = 2 A, (**g,h**) switching process of S\({}_{1}\) with ACACs, \(I_{0}\) = 10 A.  
to Figure 7, when the output current is 2 A, the auxiliary current should be larger than 2.8 A; in this experiment, the auxiliary current \(i_{\text{A\_peak}}\) is 3 A. As shown in Figure 9e,f, with the auxiliary current, the main switch realized zero-voltage turn-on. When the output current is 10 A, the auxiliary current should be larger than 5 A; in this experiment, the auxiliary current \(i_{\text{A\_peak}}\) is 6 A. As shown in Figure 9g,h, with the auxiliary current, the main switch realized zero-voltage turn-on. With the proposed ACACs, the main switches of the ITLDC realized zero-voltage turn-on. To verify the efficiency, the efficiency of the ITLDC with the proposed ACACs and without ACACs is measured by a HIOKI power analyzer PW6001 and the efficiency changes with the output power are shown in Figure 10. When the output power is small, the efficiency of the ITLDC with ACACs is slightly higher than that of the ITLDC without ACACs, and when the output power is large, the efficiency of the ITLDC with ACACs is much higher than that of the ITLDC without ACACs. It is interesting to compare the proposed ZVS method and the state-of-the-art ZVS methods for the four-switch ITLDC. The comparison results are summarized in Table 2. The auxiliary circuits, soft switching of the switches, soft switching range and current/voltage stress are employed to evaluate the ZVS methods. Each ZVS method has its own advantages. For example, in [16; 20], wide load range ZVS turn-on and turn-off for all switches is realized; in [17], wide load range soft switching is realized by the auxiliary circuit with only two switches; in [19], the ZVS is realized with no auxiliary circuits. However, most of them do not realize the full load range ZVS; thus, with the light load situation--for example, the battery floating charge stage--the converter has to work with hard switching. Many ZVS methods realize wide load range ZVS; however, the ZVS range will decrease when considering the dead time between switches. Although two ACACs are added in the proposed ZVS converter, the full load range ZVS of the main switches is realized. Furthermore, the auxiliary switches realized zero current turn-on and zero-voltage turn-off, and this ZVS method does not increase the current stress of the switches. Figure 10: The efficiency of the ITLDC.