Efficient medium and high-voltage dc-dc conversion is critical for future dc grids. This paper proposes a hybrid multilevel dc-ac converter structure that is used as the kernel of dc-dc conversion systems. Operation of the proposed dc-ac converter is suited to trapezoidal ac-voltage waveforms. Quantitative and qualitative analyses show that said trapezoidal operation reduces converter footprint, active and passive components' size, and on-state losses relative to conventional modular multilevel converters. The proposed converter is scalable to high voltages with controllable ac-voltage slope; implying tolerable dv/dt stresses on the converter transformer. Structural variations of the proposed converter with enhanced modularity and improved efficiency will be presented and discussed with regards to application in front-to-front isolated dc-dc conversion stages, and in light of said trapezoidal operation. Numerical results provide deeper insight of the presented converter designs with emphasis on system design aspects. Results obtained from a proof-of-concept 1-kW experimental test rig confirm the validity of simulation results, theoretical analyses, and simplified design equations presented in this paper.
|Original language||English (US)|
|Number of pages||15|
|Journal||IEEE Journal of Emerging and Selected Topics in Power Electronics|
|State||Published - Mar 2018|
Bibliographical notePublisher Copyright:
© 2013 IEEE.
- DC fault
- DC-DC power conversion
- Dc transformer
- Dual-active bridge (DAB)
- Modular multilevel converter (MMC)
ASJC Scopus subject areas
- Energy Engineering and Power Technology
- Electrical and Electronic Engineering