A New SST Topology Comprising Boost Three-Level AC/DC Converters for Applications in Electric Power Distribution Systems | IEEE Journals & Magazine | IEEE Xplore

A New SST Topology Comprising Boost Three-Level AC/DC Converters for Applications in Electric Power Distribution Systems

Publisher: IEEE

Abstract:

The growing interest in integrating distributed generation into the existing power distribution grid, the increase in the penetration levels of renewables, as well as the...View more

Abstract:

The growing interest in integrating distributed generation into the existing power distribution grid, the increase in the penetration levels of renewables, as well as the need to achieve a more efficient, reliable, and sustainable grid is leading to the development of new grid-interfaced power converters such as the solid-state transformer (SST). As current and voltage ratings of commercially available power semiconductor devices are normally below power ratings required in distribution systems (e.g., 13.8 kVrms), multiple modules must be connected in cascade configuration at the high-voltage (HV) side to reach higher voltage ratings as well as in parallel at the low-voltage (LV) side to achieve high current levels. A new SST topology consisting of modular boost-based three-level ac-dc converters, medium-frequency transformers with two secondary windings, and four-leg ac-dc converters is presented in this paper. When compared to similar approaches, the proposed topology comprises fewer power conversion stages, lower voltage across the semiconductor devices on the HV side, and lower current flowing through each device on the LV side. These characteristics reduce the number of series-connected modules in the HV side and parallel-connected devices in the LV side. The feasibility of the proposed topology is experimentally validated on a 500 W, 120 Vac/48 Vdc scaled-down prototype.
Page(s): 735 - 746
Date of Publication: 02 March 2017

ISSN Information:

Publisher: IEEE

I. Introduction

During the last decades, factors such as changes in the power grid structure, the increase of penetration levels of renewables, the implementation of dc grids, and the need to offer premium power quality to customers have motivated utilities to implement new power electronic interfaces (PEIs) to modernize the conventional power distribution system. One of the most helpful and promising PEI in the future power grids is the so-called solid-state transformer (SST), which has been proposed to replace the bulky fundamental-frequency transformers for several applications [1]–[7]. In addition to the functionalities of conventional transformers (e.g., galvanic isolation between networks and voltage matching between two voltage levels), the SST is capable of controlling the power flow between networks, limiting fault currents, integrating energy storage units, compensating for reactive power, improving power quality, and many others. These assets make the SST a promising technology in future smart grids at any voltage and power level [3]–[5].

References

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