A zero voltage and zero current switching three level DC/DC converter

Abstract

This paper presents a novel zero voltage and zero current switching (ZVZCS) three-Level (TL) DC/DC power converter. This converter overcomes the drawbacks presented by the conventional zero voltage switching (ZVS) three-level converter, such as high circulating energy, severe parasitic ringing on the rectifier diodes, and limited ZVS load range for the inner switches. The converter presented in this paper uses a phase shift control with a flying capacitor in the primary side to achieve ZVS for the outer switches. Additionally, the converter uses an auxiliary circuit to reset the primary current during the freewheeling stage to achieve ZCS for the inner switches. The principle of operation and the DC characteristics of the new converter are analyzed and verified on a 6kW, 100 kHz experimental prototype.