Pascal Reghem

Analytical Prediction of Eddy-Current Loss in Armature Windings of Permanent Magnet Brushless AC Machines

This paper presents an analytical model for prediction of eddy current loss in armature windings of permanent magnet brushless AC machines. The developed model can either be used in the case of internal or external rotor radial-field machines topologies. First, a 2-D exact analytical solution of magnetic field distribution in an actual geometry of slotted surface mounted PM radial flux synchronous machines is established. It involves solution of Maxwells equations in slots, airgap and PMs region. Then, magnetic vector potential solution in the slots is used for prediction of resistance limited eddy current in armature windings. Finally, results from this analytical model are compared to corresponding finite element analyses.

Modeling and optimal sizing of hybrid renewable energy system

This paper presents a new methodology of sizing optimization of a stand-alone hybrid renewable energy system. The developed approach makes use of a deterministic algorithm to minimize the life cycle cost of the system while guaranteeing the availability of the energy. Firstly, the mathematical modeling of the principal elements of the hybrid wind/PV system is exposed showing the main sizing variables. Then, the deterministic algorithm is presented and implemented to minimize the objective function which is equal to the life cycle cost of the hybrid system and finally, the obtained results are exposed and discussed.

Permeance Network Modeling of the Stator Winding Faults in Electrical Machines

The aim of this paper is to present a robust model based on permeance network method (PNM) for the diagnosis of electrical machine stator faults. The proposed model allows taking into account the local magnetic saturation of the magnetic circuit due to heavy stator fault currents and remains moderately time consuming compared to the finite elements method. Firstly, the system of algebraic equations describing the developed permeance network is written. Then, this magnetic model is coupled to the electrical differential equations describing the induction machine in presence of inter-turn stator faults. Finally, simulation results are successfully compared to the experimental results. The impact of saturation on inter-turn fault signature clearly confirms the interest of a nonlinear model based diagnostic for this fault.

Armature Reaction Magnetic Field of Tubular Linear Surface-Inset Permanent-Magnet Machines

This paper presents an exact 2-D analytical model for predicting the armature reaction magnetic field in idealized structures of permanent-magnet tubular linear machines with surface-inset mounted magnets. The armature reaction magnetic field distributions is analytically derived and compared to finite-element analyses. The analytical solution allows the prediction of the machine inductance and reluctance force in closed forms, and facilitates the evaluation of any possible partial irreversible demagnetization of the magnets. It can also be used to estimate resistance limited eddy-current losses in armature windings and permanent magnets. The developed analytical model can be advantageously used for the analysis and design of a class of linear tubular machines.

Analytical modelling of the magnetic field in axial flux permanent magnet machines with semi-closed slots at no load

This paper presents an analytical solution for prediction of the no-load magnetic field in slotted semi-closed permanent magnet axial flux synchronous machines. The technique is based on 2-D solution of the Maxwells equations using the separation of variables method, this technique is validated for two different machines. The magnetic field expressions are developed in slots regions, magnetic airgap region, slot opening region and permanent magnet region leading to an exact calculation of the slot effects on the airgap magnetic quantities. Results from this analytical model are compared to corresponding finite element analyses (FEA).

Coupled magnetic circuit method and permeance network method modeling of stator faults in induction machines

The aim of this paper is to present and compare two modeling methods of the inter-turn short circuit fault in the stator winding of a cage induction machine. The first method is a Coupled Magnetic Circuit Method (CMCM) and the second method is a Permeance Network Method (PNM) which allows taking into account the saturation effect on the fault signature. The simulation results show that by proper modeling of induction machine it is possible to detect the effect of inter-turn short circuit faults on the machine line currents. The effect of saturation on the machine line current signature is discussed. The detailed equations describing the performance of the machine in the two cases of modeling under inter-turns short circuit faults are presented. Simulation results are compared for both healthy and faulty cases.

Induction machine modelling using Permeance Network Method for dynamic simulation of air-gap eccentricity

Electrical machines diagnosis needs a modelling approach reliable and as close to the reality as possible. It is shown that by proper modelling of the induction machine it is possible to detect the effect of the different faults on the machine current and vibrations. This paper proposes a model based on permeance network method (PNM) for the simulation of faulty induction machines. The PNM allows the authors to take into account the local magnetic saturation and remains moderately time consuming compared to the finite element method. The developed permeance network of the machine is coupled to the stator phase electrical equations on one side and, on the other side, to the mechanical motion equation in order to simulate variable speed operations. The air-gap eccentricity is then taken into account in the modelling of the air-gap permeance. The effect of the eccentricity on the current and vibration signatures is discussed. Theoretical analysis for the effect of the machine eccentricity is presented.

Armature reaction field of tubular linear surface-inset permanent magnet machines

This paper presents an exact 2D analytical model for predicting the armature reaction magnetic field in idealized structures of permanent magnet tubular linear machines with surface-inset mounted magnets. The armature reaction magnetic field distributions is analytically derived and compared to finite elements analyses. The analytical solution allows the prediction of the machine inductance and reluctance force in closed forms, and facilitates the evaluation of any possible partial irreversible demagnetization of the magnets. It can also be used to estimate resistance limited eddy current losses in armature windings and permanent magnets. The developed analytical model can be advantageously used for the analysis and design of a class of linear tubular machines.

2d analytical solution of magnetic field in axial flux permanent magnet machines for the inter-turn short-circuit stator fault case

This paper presents an analytical solution for prediction of the magnetic field in slotted permanent magnet axial flux synchronous machines in the case of inter-turn short-circuit stator fault. The technique is based on 2-D solution of the Maxwells equations using the separation of variables method. The magnetic field expressions are developed in slots regions, magnetic airgap region, slot opening region and permanent magnet region leading to an exact calculation of the slot effects on the airgap magnetic quantities. Inter-turn short-circuit fault is then taken into account in the stator phases electrical equations. Simulation results illustrating the impact of the stator winding faults are presented and their comparison with those issued from coupled magnetic circuit based model proof the pertinence of the proposed approach.

Short Term Energy Storage Based on Reluctance Machine Control for Wind Diesel System

The paper presents a simulation for energy short term storage unit integrated into a stand alone hybrid wind diesel system. The energy short term storage unit is a flywheel device which is driven by a 6/4 switched reluctance machine (SRM) operating in motor and generator modes. The control strategy is developed to smooth the wind power turbulence fluctuations in order to decrease the fuel consumption by the diesel generator and to allow it a suitable operation because of its slow dynamic. The system model is implemented on Matlab-Simulink environment