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This paper assess the improvement of torque density by third harmonic injection in five-phase induction machine with two types of windings, full pitch concentrated and distributed windings. A quasi-rectangular waveform of air-gap flux density involves a quasi-uniform distribution flux density which reduces saturations hence decreasing iron losses. Tow sequence planes $\mathrm {d}_{1_{-}}\mathrm {q}_{1}$ and $\mathrm {d}_{3_{-}}\mathrm {q}_{3}$, fundamental and third respectively, are used to modeling five-phase induction machines. The required air-gap flux waveform is quasi-rectangular when fundamental and third sequence direct axes are aligned. To ensure this alignment a suitable indirect flux oriented control is used. The assessment is conducted by simulation using MATLAB.

This paper deals with the balancing and voltage control of the three-phase self-excited induction generator (SEIG) supplying a single-phase load. This mode of operation normally causes an extreme unbalance in the generator. The proposed balancing method consists in changing the value of the excitation capacitor connected to the SEIG by using switched capacitors of different values. The values of the switched capacitors are chosen according to the value of the single-phase load connected to the SEIG. The study shows that by tolerating a certain degree of unbalance, a reduced number of switched capacitors permits to feed the single-phase load with the desired voltage over a wide operating range. Using the d-q model, the dynamic performances of the SEIG are investigated. In addition, a preliminary implementation of an experimental prototype based on electromagnetic relays and an Arduino microcontroller board is carried out. The computed and experimental results are presented and compared.

International audience; Dans cet article, les auteurs présentent un modèle semi-analytique d’une machine asynchrone à cage d’écureuil en considérant la saturation magnétique locale et les courants de Foucault induits dans les barres rotoriques. Les régions du rotor et du stator sont divisées en sous-domaines élémentaires (SDs-E) caractérisés par des solutions générales au premier harmonique des équations de Maxwell en magnéto-harmonique. Ces SDs-E sont connectés dans les deux directions (i.e., selon les bords r et θ). Le calcul du champ magnétique a été validé pour plusieurs valeurs de la perméabilité relative du fer et du glissement. Toutes les grandeursélectromagnétiques ont été comparées à ceux obtenues par une méthode numérique en deux dimensions (2-D), viz., FEMM. Les résultats semi-analytiques sont satisfaisants par rapport aux numériques, en considérant l'amplitude et la forme d'onde.

International audience; Dans cet article, les auteurs présentent un modèle semi-analytique d'une machine asynchrone à cage d'écureuil en considérant la saturation magnétique locale et les courants de Foucault induits dans les barres rotoriques. Les régions du rotor et du stator sont divisées en sous-domaines élémentaires (SDs-E) caractérisés par des solutions générales au premier harmonique des équations de Maxwell en magnéto-harmonique. Ces SDs-E sont connectés dans les deux directions (i.e., selon les bords r et θ). Le calcul du champ magnétique a été validé pour plusieurs valeurs de la perméabilité relative du fer et du glissement. Toutes les grandeurs électromagnétiques ont été comparées à ceux obtenues par une méthode numérique en deux dimensions (2-D), viz., FEMM. Les résultats semi-analytiques sont satisfaisants par rapport aux numériques, en considérant l'amplitude et la forme d'onde.

International audience; Actually, the heat transfer prediction and temperature distribution in electrical machines are realized by using the finite-element method (Fem) and/or thermal equivalent circuit. The analytical resolution of partial differential equations representing the temperature distribution in electrical machines does not exist. In this paper, a 2-D exact analytical calculation of steady-state temperature distribution in rotating electrical machines by solving the heat equation in homogenous and nonhomogenous regions by using Fourier’s series and the separation of variables method is presented. It is based on the new subdomain technique where the solution depends on both directions ( r , θ ) and able to model different materials of the machine with different thermal conductivities. The heat sources are volumique power losses due to hysteresis, eddy-current, and Joule losses in all the regions of machine. A simplified method is used to determine the power losses in permanent-magnet motors. The main studied problem is conductive with conductive interface conditions, although convective heat transfer in the air gap is also investigated. The boundary conditions considered for solving the conduction problem is a convective heat transfer between the machine and external air and at the rotor internal air. The semi-analytical results are in very good agreement with those obtained by Fem, considering both amplitude and waveform.

International audience; The paper deals with the nonlinear analytical harmonic modeling (HM) of 3-phases, and 6-slots/4-poles switched reluctance machine (SRM). The proposed model consists in computing magnetic field distribution and static torque of a conventional winding distribution SRM. Because a SRM has inherently nonlinear characteristics, the analytical subdomain model which does not take into account the saturation has a limited accuracy; this is due to the assumption of infinite tooth permeability. The new analytical subdomain model based on the HM technique, favorable to beyond this limitation, is presented with the consideration of the local magnetic saturation on the teeth. The results obtained with the nonlinear analytical model (NAM) are compared with the analytical subdomainmodel (without the saturation effect) and nonlinear finite elements method solutions.

This paper presents the steady-state performances of a self-excited induction generator under unbalanced conditions. Particular interest was given to an extreme unbalance condition where a three-phase induction generator is supplying a single-phase load. The computation approach used simplifies the mathematical equations governing the operation of the generator. The adopted model for the generator-load assembly is based on the symmetrical components method. An optimization technique is used for solving the equations. Then, the performances of the generator are determined. The results for the star and delta connections are given. The computed results are validated by an experimental test bench.

A generalized two axes model of a squirrel-cage induction motor is developed This model is based on a winding function approach and the coupled magnetic circuit theory and takes into account the stator and the rotor asymmetries due to faults. This paper presents a computer simulation and experimental dynamic characteristics for a healthy induction machine, machine with one broken bar and a machine with two broken bars. The results illustrate good agreement between both simulated and experimental results. Also, the power spectral density PSD was performed to obtain a stator current spectrum.