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In this study, a wide load range zero‐voltage zero‐current switching (ZVZCS) dual‐active‐bridge DC–DC converter using auxiliary parallel networks is proposed. The outstanding feature of the proposed converter is that all of the switches are allowed to operate with zero‐voltage switching while four of the switches are allowed to operate with zero‐current switching, due to the use of two auxiliary parallel networks, which were paralleled to two active bridges, respectively. Furthermore, the circulating current losses can be reduced significantly by using unified boundary trapezoidal modulation method. Based on these merits, the proposed converter has some advantages for the wide range load variation applications with less circulating current losses. The operation principles, soft‐switching conditions and loss analyses comparison are given in this study. These benefits and characteristics mentioned above are verified from the experimental results by using a 1 kW prototype. [ABSTRACT FROM AUTHOR]

A novel high‐efficiency high step‐up pulse‐width modulation (PWM) resonant converter is proposed. It achieves high‐voltage step‐up by connecting the outputs of the boost converter cell and the isolated single‐ended PWM resonant converter cell in series, and high efficiency by zero current switching for the diode on the secondary side of the transformer of the single‐ended PWM resonant converter cell. The boost converter cell in the proposed converter can not only step‐up voltage, but also absorbs the leakage inductor energy during the turn‐off interval of the power switch to improve power conversion efficiency. Experimental results of a 100 W 35 V/200 V prototype are presented to verify the analysis results of the proposed converter. [ABSTRACT FROM AUTHOR]

A high boost ratio non‐isolated converter with a ripple‐free input current is proposed, which combines a zero‐ripple boost cell and a coupled inductor to achieve a high output voltage step‐up. A passive snubber is utilised to suppress voltage spike of the switch caused by the resonance of the leakage inductance of the coupled inductor and the parasitic capacitance of the switch. Therefore, a low‐voltage‐rated metal oxide semiconductor field effect transistor (MOSFET) with low rDS(ON) can be used to improve the efficiency of the converter. In addition, a ripple‐free input current can be achieved, making the electromagnetic interference (EMI) filter simple. Experimental results of a 100 W (40 V/200 V) prototype are presented to verify the analysis results of the proposed converter. [ABSTRACT FROM AUTHOR]