Zero-voltage-switching PWM full-bridge three-level converter

This paper proposes a novel control scheme allowing the full-bridge (FB) three-level (TL) converter to achieve zero-voltage-switching (ZVS) for the main switches while operating under three-level mode and two-level mode without penalizing the efficiency, which makes the converter adaptive to wide input voltage range. Furthermore, the voltage stress of the main switches is only half of the input voltage, which makes it very suitable in high input voltage applications. Compared with traditional FB converter, the output filter inductance of FB TL converter is significantly reduced due to lower high-frequency content of the secondary rectified voltage. Additionally the input current of the converter has quite little ripple, the input filter can be reduced. The operation principle of the FB TL converter is analyzed and verified on a 3 kW, 100 kHz prototype.