Dual-Buck Three-Phase Cyclo-Converters Without Commutation Problem

This article proposes a novel three-phase dual-buck ac–ac converters capable of both step-up and step-down operations. They use a dual-buck structure, while effectively mitigating commutation problems and eliminating the necessity for lossy snubber circuits and complex soft commutation strategies. As a result, the output voltage with less distortion can be obtained. Also, the proposed converters provide flexibility in handling a wide range of input voltage requirements. Furthermore, they can significantly reduce the requirement for shoot-through inductors, which not only reduces component count but also enhances overall efficiency. A phase-shifted PWM strategy is utilized to enhance the effective switching frequency of inductors and capacitors while maintaining the same switching frequency of semiconductor devices while optimizing performance and reliability. Notably, the proposed converters utilize power metal-oxide-semiconductor field-effect transistors (MOSFETs) without engaging their body diodes, thereby resolving the reverse recovery issue typically associated with MOSFETs body diodes. To validate the feasibility of the proposed converters, both the simulation and experimental results of the proposed converters are presented, while demonstrating the converters superior performance and practical applicability.