An Inherent Zero Voltage Switching Multilevel AC/DC Topology for High-Voltage Applications

This paper presents a multilevel converter topology that integrates a sub-multilevel converter unit with full-bridge modules. A key feature of the proposed topology is the operation of high-voltage switching devices within the full-bridge modules under Zero Voltage Switching (ZVS) conditions. This not only significantly reduces switching losses but also facilitates the use of series-connected switches in the full-bridge modules to meet high blocking voltage requirements. This topology is designed to be flexible, allowing adjustments in the number of basic units and full-bridge modules as needed. Furthermore, a method is presented for determining the appropriate magnitudes of DC voltage sources. The operation and performance of the proposed multilevel converter are validated through the simulation of a single-phase 25-level converter.