Full-bridge Three-Level Converter with the Flying Capacitor and Two Clamping Diodes

This paper proposes a chopping plus phase-shift (CPS) control for the full-bridge (FB) three-level (TL) converter to obtain the following advantages: 1) the main switches suffer only the half of the input voltage; 2) zero-voltage-switching (ZVS) is achieved for the main switches; 3) the converter has two operation modes; 4) the output filter inductance is reduced; 5) the input filter can be reduced. The flying capacitor and the two clamping diodes are analyzed, which are used to avoid the unequal voltage stress of the switches due to the asymmetrical driving of the switches. The operation principle of the FB TL converter is analyzed and verified experimentally