F. Defay

Institut Supérieur de l'Aéronautique et de l'Espace (ISAE), Tolosa de Llenguadoc, Midi-Pyrénées, France

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Publications (7)13 Total impact

  • Source
    F. Defay, A.-M. Llor, M. Fadel
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    ABSTRACT: A direct predictive control strategy is proposed for a three-phase four-level flying-capacitor (FC) inverter in this paper. The balancing of the FC voltages, a challenge in applications with small capacitors and low switching frequencies, is done without any modulation, simply using tables calculated offline. These allow the realization of fast-dynamics output currents with reduced dv / dt in the output voltages and reduced switching frequencies. Moreover, no interharmonics are created when operating at low switching frequencies and with reference currents containing multiple harmonic components, which is a key feature for active power filters. Simulations and experimental results are presented to demonstrate the excellent performance of the direct control strategy in comparison with a conventional pulsewidth-modulation control technique, mostly for operation at low switching frequencies.
    IEEE Transactions on Industrial Electronics 08/2010; · 6.50 Impact Factor
  • François DEFAY, Ana M. LLOR, Maurice FADEL
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    ABSTRACT: In this paper a direct predictive current control is proposed for a three-phase flying capacitor multilevel inverter. This control method has been applied to increase the bandwidth of the inverter, defined as the ratio between the switching frequency and the current injected frequency. The current control is applied without modulation, using pre-calculated sequence tables with pre-defined profiles. The experimental results demonstrate the excellent performance of the predictive control in terms of current bandwidth, power factor and reduced switching frequency of each commutation cell.
    01/2010;
  • F. Defay, A.M. Llor, M. Fadel
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    ABSTRACT: In this paper, a direct control of a flying capacitor inverter is proposed. This control allows to limit the number of commutations in a switching period with the use of a pre-calculated output voltage profile. A predictive control is made for the 3 phases 4 levels inverter in a active filtering operation. The advantages of this direct control is to reduce the switching frequency of the IGBTs, to use only a threshold voltage detector for flying capacitor voltages and to define offline pre-calculated switching tables. Experimental results for an active power filter application validate the performances of this control for static and dynamic conditions.
    Power Electronics and Applications, 2009. EPE '09. 13th European Conference on; 10/2009
  • Source
    F. Defay, A.-M. Llor, M. Fadel
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    ABSTRACT: Unlike traditional inverters, multicell inverters have the following advantages: lower switching frequency, high number of output levels, and less voltage constraints on the insulated-gate bipolar transistors. Significant performances are provided with this structure which is constituted with flying capacitors. This paper deals with a predictive and direct control applied to the multicell inverter for an original application of this converter: a three-phase active filter. To take advantage of the capabilities of the multicell converter in terms of redundant control states, a voltage control method of flying capacitor is added, based on the use of a switching table. Flying capacitor voltages are kept on a fixed interval, and precise voltage sensors are not necessary. The association of predictive control and voltage balancing increases considerably the bandwidth of the active filter.
    IEEE Transactions on Industrial Electronics 10/2008; · 6.50 Impact Factor
  • F. Defay, A.M. Llor, M. Fadel
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    ABSTRACT: Active power filter represents an interesting device to produce a clean electrical network. In this paper, a filter is proposed using a multicell inverter. A direct and predictive control will be applied. The use of this kind of inverters, which proposes more than two output voltage levels, allows to increase the bandwidth of the active filter. This benefit is particularly interesting to reduce the switching frequency on semiconductors. So this device could be attractive for huge power installation or high frequency network. The control of multicell inverter proposed in this paper is made on a original frame, the voltage composed frame which allows to have a particular approach of the inverter control.
    Power Electronics and Applications, 2007 European Conference on; 10/2007
  • F. Defay, A.M. Llor, M. Fadel
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    ABSTRACT: Unlike traditional inverters, multicell inverters have the following advantages: lower switching frequency, high number of output levels and less voltage constraints on the IGBT's. Significant performances are provided with this structure which is constituted with flying capacitors. This paper deals with a predictive and direct control applied to the multicell inverter. To perform the capabilities of multicell active filter, a voltage control method of flying capacitor, based on the use of a switching table, is added. Flying capacitor voltages are kept on a fixed interval and precise voltage sensors are not necessary. The association of predictive control and voltage balancing increases considerably the bandwidth of active filter.
    Industrial Electronics, 2007. ISIE 2007. IEEE International Symposium on; 07/2007
  • Source
    François Defaÿ
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    ABSTRACT: Les enjeux énergetiques liés à la qualité de la distribution de I'énergie électrique nécessitent le développement des dispositifs de filtrage actif des réseaux électriques. L'objectif de la thèse est d'utiliser un convertisseur multicellulaire afin d'obtenir une source de courant avec une très bonne bande passante (pour compenser les courants perturbateurs). Une commande directe et prédictive est appliquée à un onduleur multicellulaire à 4 niveaux. Ce type de commande permet d'utiiiser au mieux les avantages fréquentiels de cette structure de conversion d'énergie. L'utilisation de cet onduleur pour une application de filtrage actif se révèle très efficace au niveau de la compensation des harmoniques de courant. Un prototype expérimental, développe dans le cadre de la thèse nous permet de valider nos résultats obtenus tout d'abord en simulation. ABSTRACT : Energy issues related to the quality of the electrical distribution require the development of active power filtering devices. The aim of the thesis is to use a multicell inverter to obtain a current source with an excellent bandwidth. The aim of this thesis is to use a three-phase 4-levels flying capacitor inverter to perform the active power filtering operation. A direct and predictive control is applied to this inverter to obtain a good current generator in the composed frame (ba-ca). This control method has been applied to increase the bandwidth of the inverter, defined as the ratio between the switching frequency and the current frequency. The flying capacitor control has been developed without any modulation and is achieved with the use of switching tables. An experimental prototype of IOWA, developed during the thesis allows validating our results. This prototype is flexible and can be used to other applications

Publication Stats

62 Citations
13.00 Total Impact Points

Institutions

  • 2010
    • Institut Supérieur de l'Aéronautique et de l'Espace (ISAE)
      Tolosa de Llenguadoc, Midi-Pyrénées, France
  • 2008–2009
    • University of Toulouse
      Tolosa de Llenguadoc, Midi-Pyrénées, France