Quasi-continuous current transformer converter and new associated ZVS structure

This paper presents a voltage changer optimized to multiply or to divide the input voltage by an integer factor of 2, 3, 4, ..., with a very high efficiency. The paper first introduces a review of the quasi-continuous current transformer converter in a step by step fashion. The last step presents the full bidirectional zero voltage switching (ZVS) converter. The theoretical study demonstrates the way to achieve ZVS operation by only decreasing the value of the transformer magnetizing inductance. ZVS conditions (developed in the paper) lead to an interesting way to control the converter, and a discrete variable frequency control is proposed. Allowing triangular current in the transformer leads to ZVS in the expanse of higher root-mean-square (RMS) current. The evaluation of this current is also carried out in the theoretical study. An experimental implementation shows an efficiency higher than 97.5% and confirms the accuracy of the theoretical study.