Research On ZVS Half-bridge DC/DC Converter

A new type 270V input / single phase 115V output aviation static inverter(ASI) is researched in this paper. Adapting a modularized scheme, the ASI is constructed by four isolated DC-DC converters and a cascade inverter. In this paper, the research work maily focus on the DC/DC converter.First,a half-bridge DC/DC converter with modified PWM controlled method is introduced in this paper. Compared with conventional half bridge topology, a branch comprising an auxiliary switch and a diode is added. By using a modified PWM control method, the two main switches conduct symmetrically and can achieve zero-voltage switching (ZVS) easily. The auxiliary switch conducts when the two main switch turn off, and it also operates at ZCS conditions. This switch not only helps the main switches achieve ZVS, furthermore, it eliminates the oscillation between the transformer leakage inductance and the junction capacitance of two switches. In this paper the converter's operational principle is analyzed in detail. And simulation and experimental research indicate that the converter is with good performance.At the end,a half-bridge DC/DC transformer with zero voltage switching (ZVS) is presented. The converter is characterized by simple structure, ZVS, low switch voltage stress, high efficiency and high reliability. The operational principle, the output characteristics and the condition for ZVS of the switches are analyzed. The converter has also been verified by simulation and experimental.