Three-Phase Hybrid Converter With Simultaneous DC and AC Outputs

Abstract

A novel topology of three-phase hybrid converter (TP-HC) which can supply simultaneously both DC and AC loads is presented. This topology is obtained by adding three switches to T-type three-level inverter. Consequently, this converter can achieve one group of DC/DC power transformation and another three-phase three-level AC voltage outputs with adjustable amplitude. The topology and operation modes of the proposed hybrid converter are introduced. Then the working principle and the available switching states of converter are analyzed, including current path, output phase voltage level and blocking voltage of different switching states. The characteristics of three typical hybrid converters are compared. A strategy combining time-sharing modulation and virtual space vector modulation (VSVPWM) is adopted to realize simultaneous DC and AC outputs of the converter. Then the capacitance voltage balance of the DC link is realized. In order to simplify the modulation strategy, a carrier based on pulse width modulation (CBPWM)strategy is proposed. Then, boost ratio of this converter is analyzed in detail. Finally, the feasibility of the proposed topology and the effectiveness of modulation strategy are verified by simulation and experiment.

Keywords

• CBPWM
• DC and AC outputs
• hybrid converter
• three level
• time-sharing modulation strategy