Triangular Conduction Mode (TCM) Operation in a High Voltage Gain DC–DC Converter

This paper introduces an analytical approach to specify the zero-voltage switching (ZVS) condition in TCM operation without any extra circuits for a high voltage gain DC-DC converter. ZVS condition can be derived by resonant analysis while the nonlinear parasitic capacitance of the switch is carefully considered. From the ZVS condition, the required dead-time duration between the high-side and low-side switches, and the reverse inductor current can be calculated, which leads to eliminate the redundant duty cycle, and determine the current ripple. In this case, the switching frequency variation is applied to adapt to the loads, which helps to decrease the ripple inductor current and conduction loss. Moreover, Ansys SIwave and Ansys Q3D Extractor are adopted to simulate the parasitic parameters of the power loops, which enables the modification of the switching frequency to ensure full-ZVS for the switch. A 48 W high voltage gain prototype using gallium nitride (GaN) devices is implemented to verify the ZVS model with an input voltage of 48 V, an output voltage of 6 V, and a switching frequency range of 200–700 kHz.