Three-Phase Single-Stage Multiport AC-DC Converter with Integrated DC-DC Conversion Stages

A new three-phase multiport AC-DC converter with integrated DC-DC conversion stages is introduced in this paper. The converter features one three-phase AC port and three DC ports: one AC port and one DC port are bidirectional, while the remaining two DC ports are unidirectional. The proposed converter is formed by combining three sub-converters: a buck DC-DC converter, a three-phase full-bridge DC-DC converter, and a three-phase six-switch AC-DC voltage source converter (VSC). All sub-converters share the same switches to operate as a single-stage converter. The converter ensures a unity power factor at the AC port and offers galvanic isolation at one of the DC ports. All ports can be independently controlled, except for one DC port. The proposed converter topology is straightforward, using only six active switches and requiring a standard control system for operation. Additionally, when used in a microgrid, this converter can eliminate the need for two other converters, significantly reducing both the size and complexity of the system. This paper defines the workings, characteristics, and control of the proposed converter. Additionally, scaled-down prototype experimental results are provided to validate the converter.