A hybrid resonant three-level converter for renewable energy in MVDC collection systems

A hybrid resonant zero-voltage zero-current switching three-level converter is proposed in this paper, which undergoes half of the input voltage for switches. The proposed converter, utilizing two transformers, adopts IGBTs for all six power switches and operates in discontinuous current mode and can achieve zero-current switching for the four main switches and rectifier diodes over the whole load range. Hence, the switching loss is reduced. The influence of the turns ratio of auxiliary transformer and the resonant capacitance on the peak and turn-off currents is discussed in detail. The operation principles of the proposed converter are analyzed and verified by the simulation and experimental results.