Study Of A Novel ZVZCS PWM Three-level Converter

Nowadays the technology of switching power supply is gradually being perfect. However, there is no end to the demand for a high-power, high performance power supply. Three-Lever DC/DC converters are widely researched in power electronics applications, especially for high power applications. The main objective to propose Three-Level converter is to reduce voltage stress across the power switches, in order to make the low voltage stress switches applied in high input voltage DC/DC converter. With the development of soft switching, it is the study hotspot that how to combine Three-Level converter with soft switching.The paper analyzes the classical Phase-Shifted Zero-Voltage-Switching PWM TL converter which integrates the advantages of resonant converters and PWM converters. Though it realizes ZVS for the power switches, it can not eliminate the duty-cycle loss and the output rectifier diodes still suffer voltage spike. Then a novel Zero-voltage and Zero-current-switching (ZVZCS) PWM three-level converter is proposed. Voltage stress of each main switch in this converter is reduced to half of the input voltage, which makes the converter quite suitable for high input voltage applications. The ZCS condition for lagging switches under wide load range is provided by a secondary auxiliary circuit.Finally, the operation principle of Zero-voltage and Zero-current-switching PWM three-level converter is validated by the simulation analyze and the debugging experiment of 50V/20A sample device.