Design and Characterization of an Eight-Phase-137-kW Intercell Transformer Dedicated to Multicell DC-DC Stages in a Modular UPS

• Published in: IEEE transactions on power electronics Vol. 29; no. 1; pp. 45 - 55
• Main Authors: Forest, Francois, Meynard, Thierry A., Huselstein, Jean-Jacques, Flumian, Didier, Rizet, Corentin, Lacarnoy, Alain
• Format: Journal Article
• Language: English
• Published: New York, NY IEEE 01.01.2014; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Applied sciences; Batteries; Convertors; Electrical engineering; Electrical engineering. Electrical power engineering; Electrical machines; Electromagnetism; Electronic equipment and fabrication. Passive components, printed wiring boards, connectics; Electronics; Engineering Sciences; Exact sciences and technology; Intercell transformer (ICT); interleaved converters; Magnetic cores; Magnetic flux; Magnetic separation; Mathematical model; Mathematical models; Power electronics, power supplies; Transformers and inductors; Uninterruptible power supply; uninterruptible power supply (UPS); Uninterruptible power systems; Windings; Test bench; Inverter; Electric transformer; Rectifier; Design criterion; Electromagnetism; Prototype; uninterruptible power supply (UPS); Direct current convertor; Secondary cell; Power supply; Power electronics; Topology; interleaved converters; Experimental study; Optimization; Medium power; Finite element method; Intercell transformer (ICT); Interconnection; Uninterruptible power supply; Integrated circuit; Monolithic integrated circuit; Multistage circuit
• ISSN: 0885-8993; 1941-0107
• DOI: 10.1109/TPEL.2013.2248755

Recent uninterruptible power supply (UPS) systems, in the medium power range (a few 100 kW), are based on a three-power stage topology including a rectifier, an inverter, and a dc-dc converter. The dc-dc converter ensures the charger/discharger function necessary for battery management. The monolithic intercell transformer (ICT) described in this paper is dedicated to such a charger/discharger, of which the nominal power is 137 kW. This dc-dc converter is comprised of eight interleaved cells that are interconnected by the ICT. The first part of this paper briefly presents the full UPS system and the topology of the eight-cell charger/discharger arranged around the eight-phase monolithic ICT. The second part suggests a model and emphasizes the design specificities of the monolithic ICT. The final design is provided by an optimization routine, checked in the end by different 2-D and 3-D finite-element simulations, both electromagnetic and thermal. The third part describes the construction of the ICT prototype. It is then placed in a test bench that reproduces the conditions of future operations and provides current balance conditions. Finally, the experimental results obtained for the 137-kW nominal power validate design parameters and confirm the interest of the ICT solution.