Zero-voltage-switching PWM three-level converter with two clamping diodes

A zero-voltage-switching pulsewidth-modulation three-level (ZVS PWM TL) converter realizes ZVS for the switches with the use of the leakage inductance (or external resonant inductance) and the output capacitors of the switches, however, the rectifier diodes suffer from reverse recovery which results in oscillation and voltage spike. In order to solve this problem, this paper proposes a novel ZVS PWM TL converter, which introduces two clamping diodes to the basic TL converter to eliminate the oscillation and clamp the rectified voltage to the reflected input voltage; in the meanwhile, all the switches keep to realize ZVS. Furthermore, the proposed ZVS PWM TL converter can be simplified by removing the two freewheeling diodes. The operation principle of the novel converter and the simplified converter are analyzed and are verified by a prototype converter. The experimental results are also included in this paper.