 |
 |
EPE Journal Volume 19-4 - Papers
- UNIFLEX–PM – A Key-Enabling Technology for Future European Electricity Networks
- Description and Efficiency Comparison of Two 25kVA DC/AC Isolation Modules
- Control Challenges and Solutions for a Multi-cellular Converter for Use in Electricity Networks
- Power Flow Control through the UNIFLEX-PM under Different Network Conditions
- Short-Circuit Analysis of the Uniflex-PM using Stationary and Natural Reference Frame Control
- Dependability and Impact Analysis for a Universal and Flexible Power Management System
- Construction and Testing of the 3.3 kV, 300 kVA UNIFLEX-PM Prototype
EPE Journal Volume 19-4 - Editorial
By Andrew Hyde
"Advanced Power Converters for Universal and Flexible Power Management in Future Electricity Networks: The UNIFLEX-PM project", Written by Andrew Hyde
EPE Journal Volume 19-4 - Papers
By Florin Iov; Frede Blaabjerg; Jon Clare; Pat Wheeler; Alfred Rufer; Andrew Hyde
More “green” power provided by Distributed Generation will enter into the European electricity network in the near future. In order to control the power flow and to ensure proper and secure operation of this future grid, with an increased level of the renewable power, new power electronic converters for grid connection of renewable sources are needed. These power converters must be able to provide intelligent power management as well as ancillary services. This paper presents an overview of an advanced power converter for universal and flexible power management that can enable the large scale-integration of dispersed generation into these future networks. The overall structure and the control requirements that are to be placed upon this converter are given. Furthermore, some possible applications as well as the benefits of using this converter are presented.
By Daniel Siemaszko; Frédéric Zurkinden; Lukas Fleischli; Irma Villar; Yales R. De Novaes; Alfred Rufer.
In the frame of the European project UNIFLEX-PM, two AC/AC converter topologies have been studied and implemented. Both converters, rated for 25 kVA, are isolated by a medium frequency power transformer. The first topology is based on a dual active bridge containing two additional voltage source inverters for the connection of both DC links to the interfaced grids. The second topology is based on a cycloconverter for the connection of the secondary side of the transformer to the grid without a DC link capacitor. Both topologies have an identical primary side so the efficiency study is focussed on the chain link from one DC link to a 25 kW output load. Experimental efficiencies are compared to theoretical expectations. Due to soft-switching operation in the dual active-bridge, the cycloconverter based solution shows a lower efficiency than in the symmetrical topology.
By Alan J. Watson, HQS Dang, Patrick W. Wheeler, Jon C. Clare, Gopal Mondal, Stephan Kenzelmann, Alfred R. Rufer, Yales R. De Novaes
This paper presents the concept of a multi-cellular power converter structure targeted towards use in future electricity networks. Control of such a converter is challenging because of the distributed energy storage intrinsic to the concept. If the energy flow through the converter is not carefully controlled poor performance and even shutdown of the converter may result. This paper details the operation of such a converter and presents an example of a control scheme which can achieve the desired performance. Validations of the converter concept and the control principles are provided by experimental results at low voltage using a two port prototype.
By Stefano Bifaretti; Pericle Zanchetta; Mihai Ciobotaru; Florin Iov; Jon C. Clare
The future electricity network has to be able to manage energy coming from different grids as well as from Renewable Energy Sources (RES) and other Distributed Generation (DG) systems. Advanced power electronic converters, like the Universal and Flexible Power Management (UNIFLEX-PM) structure, can provide the means to control power flow and assure proper and secure operation of future networks. This paper presents the analysis and design of advanced control techniques for the back-to-back three-phase AC-DC-AC multi-level converter employed in the UNIFLEX-PM system. The proposed strategies have been successfully tested through simulation for bidirectional power flow operation with different grid operating conditions such as voltage unbalance, frequency variation and harmonic distortion.
By Mihai Ciobotaru; Florin Iov; Stefano Bifaretti; Pericle Zanchetta
In order to allow a sustainable energy future based on a large share of Distributed Generation (DG), there is a clear need to prepare the European electricity system for the large-scale integration of both renewable and other distributed energy sources. Advanced power electronic converters for DG will be needed to control the power flow and to ensure proper and secure operation of this future grid with an increased level of the renewable power. These power converters must be able to provide intelligent power management as well as ancillary services. This paper presents a short-circuit analysis of a multi-level H-bridge power converter for Universal and Flexible Power Management (UNIFLEX-PM) in Future Electricity Network. The analysis is made for two different control strategies, namely the stationary and the natural reference frame control. Selected simulation results are presented in order to compare the behavior of the two control strategies under various grid short-circuits.
By Micaela Caserza Magro; Stefano Savio
This paper presents the final results of the activities carried out by the authors to estimate the reliability and availability performances of an innovative modular power conversion architecture, developed within the UNIFLEX-PM (Universal and Flexible Power Management) EU project. The performed study addresses also the analysis of the effects on system stochastic performances deriving from basic components wear out phenomena, and the ones deriving from the adoption of different redundancy strategies and maintenance policies. The UNIFLEX-PM architecture represents an innovative solution for power management in the distribution networks, thus the reliability and availability studies have been focused on obtaining basic figures useful to define the effectiveness of the proposed solution through comparison with a power converter architecture already used for building commercial products and assumed as the reference case. The results show that with a suitable technological choice for some critical basic components (such as the DC link capacitors), the UNIFLEX-PM stochastic performances are fully comparable with the ones provided by the commercial solution.
By Alan J. Watson; Gopal Mondal; HQS Dang; Patrick W. Wheeler; Jon C. Clare
This paper presents details of the experimental implementation of a prototype multi-cellular converter for application in future electricity supply networks. Such a converter is capable of independently controlling power flow between various parts of an electricity grid, interfacing renewable energy systems directly into the grid and connecting grids of different voltages and frequency. An outline of the challenges for converter construction are presented as well as experimental results for the converter operating at 300kVA whilst connected between two 3.3 kV grids.
EPE Journal Volume 19-4: Other
By B. Sneyers
EPE Wind Energy Chapter Symposium 2010, Staffordshire University, Stafford, UK , 15th and 16th of April 2010
By Various
Other events announced in EPE Journal 19-4