EPE Journal Volume 23-2 
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EPE Journal Volume 23-2 - Editorial
EPE Journal Volume 23-2 - Papers



 EPE Journal Volume 23-2 - Editorial 

EPE Association, EPE ECCE Europe: plans for the coming years  [Details]
By J.L. Thomas & B. Sneyers

EPE ’13 ECCE Europe closed its doors on Thursday 5 September with a nice feeling of well-done work. Despite the unusual and sometimes unbearable heat, technical exchanges have been intense and the average technical level was good. Lecture and dialogue sessions are highly valued and there seems to be a general request to give more time to dialogue sessions. We are compiling the results of the received enquiries and will see that the organization of the next conference will take the remarks into account.


 EPE Journal Volume 23-2 - Papers 

System-Level Analysis and Optimization of Air Cooling with Radial Fans  [Details]
By Th. B. Gradinger
A computational model and a method is presented for the optimization of air cooling for power electronics in terms of thermal performance, cooling-system size and acoustic noise, which are key parameters for power-electronic applications. A number of case studies is performed, showing the relationship and the trade-offs between these quantities.
In general increasing thermal performance leads to bigger size and/or higher noise, while lowering noise for constant thermal performance increases size. Within the basic physical limits, optimization is possible, which must be carried out at system level, as the results cannot be found by separately optimizing individual cooling-system components. Examples are the enlargement of the heat sink or the addition of volume for porous duct lining, which both can lead to a smaller overall system for fixed thermal performance and noise.
The trade-off between thermal performance, size and noise worked out for air-cooling systems with radial fans is expected to be of general nature, applying to any kind of cooling system. In future work, the present method could be used to compare air cooling with other types of cooling systems, in particular water cooling and two-phase cooling.

A Reduced Device-Count Hybrid Multilevel Inverter Topology with single DC Source and Improved Fault Tolerance  [Details]
By Rajeevan. P. P; K.Gopakumar
A new hybrid multilevel power converter topology is presented in this paper. The proposed power converter topology uses only one DC source and floating capacitors charged to asymmetrical voltage levels, are used for generating different voltage levels. The SVPWM based control strategy used in this converter maintains the capacitor voltages at the required levels in the entire modulation range including the over-modulation region. For the voltage levels: nine and above, the number of components required in the proposed topology is significantly lower, compared to the conventional multilevel inverter topologies. The number of capacitors required in this topology reduces drastically compared to the conventional flying capacitor topology, when the number of levels in the inverter output increases. This topology has better fault tolerance, as it is capable of operating with reduced number of levels, in the entire modulation range, in the event of any failure in the H-bridges. The transient as well as the steady state performance of the nine-level version of the proposed topology is experimentally verified in the entire modulation range including the over-modulation region.

Analytical Evaluation of Switching Characteristics in Five-Phase Drives with Discontinuous Space Vector Pulse Width Modulation Techniques  [Details]
By J. Prieto; F. Barrero; E. Levi; S. Toral; M. Jones; M. J. Durán
This paper deals with flux harmonic distortion factor (HDF) and current ripple analysis for various discontinuous space vector PWM (SVPWM) techniques, applicable in conjunction with five-phase two-level inverter-fed ac motor drives. The analysis is based on the application of the recently developed polygon approach for multiphase systems. The results are compared throughout with the corresponding continuous SVPWM techniques. Two different SVPWM methods, based on different selections of the active vectors, are encompassed by the analysis. The analytical study is supported with simulation and experimental result, obtained using a five-phase induction motor.

Operation and Control of VSC-HVDC Multiterminal Grids for Offshore Wind  [Details]
By A. Egea-Alvarez; A. Junyent-Ferre; O. Gomis-Bellmunt; Jun Liang Janaka Ekanayake
The control and operation of a multiterminal VSC-HVDC grid for offshore wind power under normal and fault conditions are described. The paper addresses maintaining the DC voltage during electrical faults and power reduction methods using fixed speed induction generators.

Modeling, Control and Experimental Validation of a Flywheel-Based Energy Storage Device  [Details]
By Fr. Díaz-González; A. Sumper; O. Gomis-Bellmunt; R. Villafafila-Robles
This work deals with the modeling, control and experimental validation of a flywheel-based energy storage device. The system is based on a low-speed rotating disk mechanically coupled to a Permanent Magnet Synchronous Machine (PMSM). The electrical power is exchanged with the external grid by means of a set of back-to-back power converters. These power electronics control the speed of the machine, and thus the active power absorbed or injected by the device, and also regulate the reactive power at the point of common coupling with the external grid. Vector control techniques are used for designing the converter controllers: a field oriented vector control algorithm is implemented for governing the servomotor while an instantaneous power theory-based algorithm is used to manage the active and reactive currents flowing from the grid side converter. The control implementation in the experimental setup has been carried out by means of programming Digital Signal Processors (DSP’s). The modeling and control system design has been validated after executing several experiments. Other characteristics such as the torque losses of the system as well as the system performance concerning energy rating, power rating and energy efficiency characteristics are determined experimentally.