Three-Level Buck Quasi-Square-Wave dc-dc Converter

The challenges for future more electric aviation requires the investigation of new topologies and technologies able to switch at high frequencies. The proposal of this paper is to apply quasi-square-wave (QSW) technique to a three-level buck converter. On QSW, the demagnetization of the power inductor is allowed to reach zero or even negative values of current, and thus zero voltage switching (ZVS) is achieved. By soft-switching, the converter can be optimized to efficiency increase or weight/volume reduction. The limits and conditions for a three-level buck converter are defined in the paper. Experimental validation is obtained via a 50 kW-rated prototype, where two continuous conduction mode (CCM) and two QSW scenarios are compared.