EMPOWER

European Research Council Consolidator Grant (ERC CoG) Project

More than a century ago, the invention of alternating current (AC) transformer has made AC the preferred choice over the direct current (DC) technologies. Line AC transformers are bulky but simple and reliable devices, made out of copper and iron, providing voltage adaptation and galvanic isolation in AC power systems.

Currently, DC technology is increasing its presence in AC power systems, enabled by progress in semiconductor devices and power electronics based energy conversion. DC power distribution networks can effectively support energy transformation and high penetration of distributed energy resources and energy storage integration (both increasingly being DC by nature) in future energy systems. Despite this shift towards the DC power distribution networks, DC Transformer, offering AC transformer like features (and beyond) does not exist, either conceptually or practically.

To enable the next (r)evolution in power systems, the EMPOWER project will develop the DC Transformer, a novel, flexible, highly efficient, compact, and reliable conversion principle for seamless energy routing in high-power DC distribution networks. Through a holistic approach, novel concepts, integration and optimization, we will demonstrate new design paradigms for galvanically-isolated power conversion. Our approach relies on resonant conversion utilizing high-voltage semiconductor devices in combination with high-frequency magnetic materials. We propose a new approach for the DC Transformer, avoiding active power flow control and instead utilizing control effort for the safety and protection. The DC Transformer will unify functions of a power converter and a protection device into a single power electronics system, improving drastically the conversion efficiency, reliability and power density in future DC power distribution networks. The success of this project will place Europe at the edge of reliable, efficient and safe energy distribution and transmission technologies.

The EMPOWER project related publications:

Power Reversal Algorithm for Resonant Direct Current Transformers for DC Networks

R. P. Barcelos; J. Kucka; D. Dujic 

IEEE Access. 2022. Vol. 10, p. 127117-127127. DOI : 10.1109/ACCESS.2022.3225673.

Winding Geometry Impact on High Power Medium Frequency Transformer Design

N. Djekanovic; D. Dujic 

2022. 14th International Symposium on Industrial Electronics – INDEL 2022, Banja Luka, Bosnia and Herzegovina, November 9-11, 2022.

Copper Pipes as Medium Frequency Transformer Windings

N. Djekanovic; D. Dujic 

IEEE Access. 2022. Vol. 10, p. 109431-109445. DOI : 10.1109/ACCESS.2022.3214651.

Design Optimization of a MW-level Medium Frequency Transformer

N. Djekanovic; D. Dujic 

2022. PCIM Europe 2022, Nürnberg, Germany, May 10-12, 2022. DOI : 10.30420/565822101.

SOFTGATE – An IGCT Gate Unit for Soft Switching

J. Kucka; D. Dujic 

2022. PCIM Europe 2022, Nurnberg, Germany, May 10-12, 2022. DOI : 10.30420/565822047.

Shoot-Through Protection for an IGCT-Based ZVS Resonant DC Transformer

J. Kucka; D. Dujic 

IEEE Transactions on Industrial Electronics. 2022.  p. 1-1. DOI : 10.1109/TIE.2022.3170614.

Resonant IGCT Soft-Switching: ZVS or ZCS

G. Ulissi; J. Kucka; U. Vemulapati; T. Stiasny; D. Dujic 

IEEE Transactions on Power Electronics. 2022.  p. 1-1. DOI : 10.1109/TPEL.2022.3170114.

Direct Current Transformer Impact on the DC Power Distribution Networks

R. P. Barcelos; D. Dujic 

IEEE Transactions on Smart Grid. 2022.  p. 1-1. DOI : 10.1109/TSG.2022.3162310.

Modeling and Characterization of Natural-Convection Oil-Based Insulation for Medium Frequency Transformers

N. Djekanovic; D. Dujic 

2022. IEEE Applied Power Electronics Conference and Exposition (APEC 2022), Houston, TX, USA, March 20-24, 2022. p. 604-610. DOI : 10.1109/APEC43599.2022.9773591.

High Frequency Operation of Series-Connected IGCTs for Resonant Converters

G. Ulissi; U. Vemulapati; T. Stiasny; D. Dujic 

IEEE Transactions on Power Electronics. 2021-12-02. Vol. 37, num. 5, p. 5664-5674. DOI : 10.1109/TPEL.2021.3132200.

Current Limiting in Overload Conditions of an LLC-Converter-Based DC Transformer

J. Kucka; D. Dujic 

IEEE Transactions on Power Electronics. 2021-02-18. Vol. 36, num. 9, p. 10660-10672. DOI : 10.1109/TPEL.2021.3060106.

An IGCT Gate Unit for Zero-Voltage-Switching Resonant DC Transformer Applications

J. Kucka; D. Dujic 

IEEE Transactions on Industrial Electronics. 2021.  p. 1-1. DOI : 10.1109/TIE.2021.3128923.

Nodal Impedance Assessment in DC Power Distribution Networks

R. Pillon Barcelos; D. Dujic 

2021. 22nd IEEE Workshop on Control and Modeling for Power Electronics (COMPEL 2021), Virtual Event, November 2-5, 2021. DOI : 10.1109/COMPEL52922.2021.9646008.

Thermally-Compensated Magnetic Core Loss Model for Time-Domain Simulations of Electrical Circuits

N. Djekanovic; M. Luo; D. Dujic 

IEEE Transactions on Power Electronics. 2021.  p. 1-1. DOI : 10.1109/TPEL.2021.3053303.

Equal Loss Distribution in Duty-Cycle Controlled H-Bridge LLC Resonant Converters

J. Kucka; D. Dujic 

IEEE Transactions on Power Electronics. 2021. Vol. 36, p. 4937-4941. DOI : 10.1109/TPEL.2020.3028879.

Modeling and Integrating Losses of Magnetic Components Into Time-Domain Electric Circuit Simulations

N. Djekanovic; M. Luo; D. Dujic 

2020. The 2020 International Power Electronics and Motion Conference – IPEMC 2020 ECCE Asia, Nanjing, China (virtual), Nov 29-Dec 02, 2020. p. 1055-1062. DOI : 10.1109/IPEMC-ECCEAsia48364.2020.9367883.

Smooth Power Direction Transition of a Bidirectional LLC Resonant Converter for DC Transformer Applications

J. Kucka; D. Dujic 

IEEE Transactions on Power Electronics. 2020.  p. 1-1. DOI : 10.1109/TPEL.2020.3038467.

Integrated Simulation Approach to Loss Calculations of Power Converter Systems

N. Djekanovic; M. Luo; D. Dujic 

2020. PCIM Europe digital days 2020, Online, July, 7-8, 2020.