Zero-voltage-switching multi-resonant three-level converters

This paper proposes a new family of zero-voltage-switching multi-resonant three-level converters (ZVS-MR-TLCs), which is derived by introducing a LCC multi-resonant network to the basic three-level converters. The unique arrangement of a multi-resonant network results in absorption of all major parasitic components in the resonant circuit, including switch output capacitor, diode junction capacitor and transformer leakage inductor. Compared with the traditional multi-resonant converters (MRCs), which is a two-level converter, the proposed converters achieve ZVS in a wider load range, reduce the voltage stress on the switches and diodes, and the filter can be reduced significantly. Buck ZVS-MR-TLC is taken as the example to illustrate the operation principle, characteristics and the advantages over the buck ZVS-MRC. A 1 kW prototype converter is built in our lab to verify the theoretical analysis.