EPE Journal Volume 12-2 
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EPE Journal Volume 12-2 - Editorial
EPE Journal Volume 12-2 - Papers



 EPE Journal Volume 12-2 - Editorial 

EPE 2003, Toulouse, France, the 10th European Conference on Power Electronics and Applications (2-4 September 2004)  [Details]
By B. de Fornel

The Editorial of the EPE Journal Volume 12 N°2, "EPE 2003, Toulouse, France, the 10th European Conference on Power Electronics and Applications (2-4 September 2004)", written by Prof. Bernard de Fornel, the Conference Chairman of EPE 2003.


 EPE Journal Volume 12-2 - Papers 

Improved Thermal Modelling of Magnetic Components for Power Electronics  [Details]
By A. Van den Bossche; V. Valchev; J. Melkebeek

An improved thermal modelling of convection and radiation heat transfer for magnetic components for power electronics is presented. The proposed model of convection heat transfer uses more precise values of the exponents in the presentation of the convection coefficient hc as well as a reduced surface of the component. The model for radiation includes precise values of the emissivity of the component surface and also a reduced ‘envelope’ surface. Accurate thermal measurements of two experimental models (box shape and transformer shape, size EE42) were done for four different kinds of surfaces of the models to derive and verify the proposed models. The improved models can be used in an accurate thermal design of magnetic components.

Stacked Multicell Converter (SMC): Topology and Control  [Details]
By G. Gateau; T.A. Meynard; L. Delmas; H. Foch

A new topology of multilevel converter is presented in this paper. This new topology called SMC (Stacked Multicell Converter) is represented on Fig. 1 and allow to increase input voltage level compared with the imbricated cells converter, while decreasing the stored energy in the converter. The topology consists of a hybrid association of commutation cell making possible to share the voltage constraint on several switches, and also to improve the output waveforms of the converter in terms of number of levels and switching frequency. Following the introduction, we make a presentation of the topology and we will explain in detail how it works. We will give in the third part some explanation about the control of the SMC converter. Before some conclusions about this work, some simulations and experimental results obtain on a 50 kVA experimental set-up will be presented.

Fuzzy Logic Based Gains Determination of Induction Motor Flux Observers  [Details]
By B. Berthereau; B. Robyns; J. P. Hautier

It is proposed in this paper a method to compute gains of induction motor flux observers, based on fuzzy logic associated to a theoretical sensitivity analysis. The theoretical analysis, taking the magnetic saturation into account, allows to study the observer sensitivity to all parameter uncertainties. The fuzzy logic associated to the theoretical analysis allows to determine observer gains which optimize together dynamics and sensitivity criteria. Although the theoretical sensitivity analysis may be developed for observers in any reference frame, the proposed method is applied in this paper respectively to a reduced and a full order flux observers based on the Park model in the stator reference frame only. The proposed method is validated by experiments on a 750W induction motor.

A Space Vector Modulation Scheme for a Dual Two Level Inverter fed Open-End Winding Induction Motor Drive for the Elimination of Zero Sequence Currents
By V. T. Somasekhar; K. Gopakumar; E. G. Shivakumar; S. K. Sinha

The dual two-level inverter fed open-end winding induction motor drive gives voltage space phasor locations similar to a three- level inverter fed induction motor drive. The dual inverter scheme renders advantages such as redundancy of the space vector combinations for the same number of space vector locations and the absence of neutral point fluctuations. In a dual-inverter scheme, a total of 64 space-vector combinations are distributed over 19 space vector locations compared to 27 space-vector combinations distributed over the same number of locations in a three-level inverter. The common mode voltages (the harmonics of the triplen order) need to be suppressed by transformer isolation or the use of harmonic filters. In this paper, a space vector modulation scheme for the suppression of zero sequence currents (the harmonics of the triplen order) for a dual two-level inverter fed open-end winding induction motor drive is described. The proposed scheme does not require bulky transformers or harmonic filters for the elimination of the zero sequence currents. The proposed space vector PWM is based on the observation that certain voltage space-vector combinations in the dual inverter scheme do not contribute to the triplen harmonics and hence the PWM scheme that exclusively employs these combinations is used to eliminate the triplen harmonic currents.

An Experimental Investigation of Fuzzy Logic Speed Control in Permanent Magnet Synchronous Motor Drives  [Details]
By Z. Ibrahim; E. Levi

One possible application of artificial intelligence in motion control is the use of a fuzzy logic (FL) speed controller. Regardless of all the work, it appears that a detailed investigation of the drive behaviour under FL speed control, using an experimental rig, is still missing. This paper provides an in-depth report on operation of a vector controlled permanent magnet synchronous motor subjected to FL speed control. The transients studied include speed response to large step speed command from standstill with nominal inertia and with an increased inertia, response to small step speed reference change with nominal inertia and with an increased inertia, and response to step load torque application. The transient behaviour is examined for various initial speed settings, so that an insight into the impact of the operating point on the controller behaviour is enabled. It is shown that the reference speed at which certain transient is initiated may strongly influence the speed response obtainable with constant parameter FL speed controller.

Power Electronic Converters Devoted to Stand-Alone Wind-Energy Generating Systems  [Details]
By L. Solero

Small to medium rating (up to 25 kW) wind generators are usually used in stand-alone generation-battery systems in remote areas where the cost of transmitting energy is prohibitive. Wind-energy generating systems, operating at variable-speed, need power electronic converters in order to achieve best wind energy exploitation. Selection of the most suitable converter topology for wind energy generating systems depends on the medium amount of wind available, the user devices voltage level, the sizing and the number of semiconductor and passive power components used in the electronic converter. This paper deals with prototypal generating systems composed of direct-drive PM synchronous generator, diode bridge rectifier, d.c.-d.c. converter and storage battery. Different d.c.-d.c. converter topologies are analyzed: first theoretical investigations highlight the clear superiority of step-up converter and step-down converter with respect to the other topologies. Computer simulations allowed an exhaustive investigation of both the step-up and the step-down converter configurations. Experimental comparison between different power electronic converter topologies for wind-energy generation was achieved during the carried out laboratory tests on a prototypal system.