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This paper presents a performance analysis of four topologies of permanent magnet synchronous generators (PMSG) generating power for a 3 kW, 220 V, three-phase, Y-connected resistive load, based on a methodology for the optimal design of PMSG using ferrite permanent magnets. The optimal designs of the machines, intended for small wind turbines, use multidisciplinary optimization models and a deterministic algorithm. As high power density is desired, only flux concentration topologies that allow high values of magnetic induction in the air gap were proposed, including inner and outer rotor machines. For the inner rotor conventional machines, both an integer and a fractional number of slots per pole per phase were proposed. A conventional and a vernier radial flux machine, both of them with outer rotor and fractional number of slots per pole per phase, were also considered. After validation of each optimal design by a finite element analysis software, the more convenient number of pole for each topology was identified, observing that the vernier machine presented the lowest torque ripple, the highest power density and the lowest active material cost among the four topologies of PMSGs.

International audience; The present paper deals with a large multidisciplinary design optimization (MDO) applied to a wind turbine permanent magnet synchronous generator (PMSG). The multidisciplinary nature of the model allows reliable results, but it demands high complexity and a large number of variables. Furthermore, to calculate the wind turbine energy production it is necessary to include several operating points in the model, increasing even more the dimension of the problem. To deal with this large optimization problem, the sequential quadratic programming (SQP) algorithm has been chosen. The results show that, besides the model complexity, the solution is obtained fast.

International audience; This paper presents the multiphysics design optimization of a permanent magnet synchronous generator (PMSG). A medium-power wind turbine (55 kW) is taken as the basis for the design optimization, whereas reducing its cost is the optimization goal. The design comprises the multiphysics generator model and the cost and losses models of the grid connection static power converters (SPC). The power converter command strategy is analyzed as it influences the system cost. Papers that dealt with the optimal design of the PMSGs usually did not consider the SPC cost and losses in the total system cost. The analysis of three power converter command strategies, implemented in the multidisciplinary design optimization, aims to define the phase angle of the generator current that leads to the lowest cost of the system composed by the generator and power converter.

This paper presents the multidisciplinary design optimization (MDO) of a WECS permanent magnet synchronous generator (PMSG). The MDO is applied to a medium power WECS (55 kW) with the objective of reducing its cost. The WECS model includes, in addition to the model of the PMSG, cost and losses models of the power converter. The wind turbine cost is not included in the model. Although numerous papers discuss the optimal design of the PMSG, few examine the influence of power converter cost and losses in WECS total cost. The optimal design methodology proposed here produced three different WECS, each to a different phase angle of the current. The results show that the current phase angle affects the costs of the PMSG and of the power converter differently. The result of the optimization allowed to define the phase angle of the current which minimizes the total cost of the WECS.

This paper shows the results of an optimization strategy that takes into account the annual wind profile of a wind turbine to minimize the generator cost and maximize the energy yield. The optimally designed machine is a 3-phase permanent magnet synchronous generator with 48 poles and 30 kW for direct drive wind turbines. The energy yield is considered in the optimization method by including the cost of losses in the objective function, which is then the sum of cost of losses, cost of materials and structure costs. To show the advantages of employing this strategy, the results of a standard optimization strategy, which minimizes the generator costs not regarding energy production, are also presented and compared. It is shown that this strategy results in a machine that produces more energy during its lifetime, which compensates its higher cost. Finite element analysis software is used to verify and validate the resulting machine.

The paper presents the optimum design of a Permanent Magnet Synchronous Generator for wind power applications. The proposed optimization strategy deals with two contradictory objectives: to reduce generator costs and to raise the energy yield. This task is accomplished by maximizing the difference between the energy proceeds and the generator costs. The generator operating cycle is taken into account by a Weibull function that represents the wind profile for a fictitious site. A thermal model is adopted to evaluate the winding temperature and prevent overheating. The optimally designed machine is a 3-phase generator for 40 kW direct drive wind turbines. The results show that this strategy would produce a cost-effective machine.

This paper presents a mathematical model of a three-phase induction motor taking into consideration the interbar contacts. Several models have been available in the references. However, they consider the rotor of the induction motor as being constituted either a three-phase or a squirrel cage even if it operates under stator and/or rotor faults condition. Nonetheless, the contact between a bar and the iron core for the machine has to be considered, especially when a rotor fault occurs. It is obvious that rotor currents are under the influence of rotor constitution materials. So, the paper aim’s concerns a transient model of the induction motors which can consider the rotor broken bars defect. Despite its increasing complexity, it could be able to provide with useful indications for diagnostic purposes. This model is advocated for the simulation of motors behavior under rotor defect which takes into account the interbar currents. The proposed technique is based on the mesh model analysis of the squirrel cage. As low power induction motors are prevalent in industrial plants, we pay a special attention on them. Notwithstanding, additional currents are due to the contact between the non-insulated bar constituting the squirrel cage to the rotor iron core. The monitoring of induction motors is predominantly made through the stator current analysis of the motor when it operates at nominal condition. Moreover, this one is observed in steady state operating system, knowing that the motor is generally fed by a sinusoidal supply. Consequently, simulation results showed in this paper prove the effectiveness of the proposed approach, and the impact of interbar resistance both on the model and the line current spectrum for the diagnostic. An experimental test proves the effectiveness of this model.

This Ph.D. dissertation presents a multidisciplinary optimum design methodology to permanent magnet synchronous generators applied to wind power. Such a methodology considers the electrical, the geometrical, the thermal, the electronic, the mechanical and the economical behaviors of the wind turbine. The wind occurrence curve, modelled by a statistical density function, is also take into account by the proposed design methodology. Considering this curve in the optimal design allows to calculate the amount of energy produced by the wind turbine, which operates under variable speed and power by the influence of the actual wind speed. The proposal of using the optimization in the design is to enhances the competitiveness of wind power by designing a generator with a good relation between its cost and its capacity to generate energy. Several studies are addressed to electrical machines optimum design related to wind power, however, few have presented a method able to estimate the wind turbine energy generation, which is mandatory to obtain a cost-effective generator. Further, the electric generator in-depth multidisciplinary aspects have been considered by the proposed method in more detail than other studies found in literature. Take into consideration all these aspects results in a large optimization problem that has approximately 2000 variables, among which approximately 250 have constraints imposed on. A deterministic optimization algorithm has been chosen to deal with this problem. Such an algorithm is capable of finding the solution within few iterations and a short time thanks to the computation of the Jacobean matrix, containing the exact gradients of the model (used to describe the wind turbine behavior) outputs. The presented results explore the proposed methodology potential. The first optimal design performed minimizes the generator active material cost, presenting a significant cost reduction compared to a non-optimal generator. Next, the contradiction between the generator cost and its efficiency is analyzed and the importance of including the wind turbine energy generation into the generator design becomes evident. Using the estimated wind turbine generated energy, the generator with maximum net earnings (equal to the wind turbine energy proceeds less the generator cost) has been obtained. This generator has a good ratio between its cost and capability to generate energy. Then, sensibility analysis have been carried out to verify how the electricity price and the annual mean wind speed influence the design. Finally, two wind turbines with different diameters and rated wind speeds have been employed, considering three distinct wind profiles. These results provide the generators more suited to each wind turbine applied to each wind profile, showing that the proposed design methodology has the ability to helps choosing the wind turbine adequate to each wind farm., Cette Thèse présente une méthodologie pour la conception optimale multidisciplinaire des générateurs synchrones à aimants permanents appliqués à l'énergie éolienne. Telle méthodologie prend en compte les comportements électriques, géométriques, thermiques, électroniques, mécaniques et économiques de l'éolienne. La courbe d'occurrence du vent, modélisée par une fonction de densité statistique, est également prise en compte par la méthodologie de conception proposée. Considérer cette courbe dans la conception optimale permet de calculer la quantité d'énergie produite par l'éolienne, qui fonctionne sous vitesse et puissance variables par l'influence de la vitesse du vent. La proposition d'utiliser l'optimisation dans la conception est d'améliorer la compétitivité de l'énergie éolienne en concevant un générateur avec une bonne relation entre son coût et sa capacité de produire de l'énergie. Plusieurs études portent sur la conception optimale des machines électriques liées à l'énergie éolienne, mais peu ont présenté une méthode permettant d'estimer la production d'énergie éolienne, ce qui est obligatoire pour obtenir un générateur rentable. De plus, les aspects multidisciplinaires approfondis du générateur électrique ont été considérés par la méthode proposée plus en détail que d'autres études trouvées dans la littérature. Prendre en compte tous ces aspects entraîne un grand problème d'optimisation qui compte environ 2000 variables, dont environ 250 ont des contraintes imposées. Un algorithme d'optimisation déterministe a été choisi pour traiter ce problème. Un tel algorithme est capable de trouver la solution en quelques itérations et un court laps de temps grâce au calcul de la matrice jacobienne, contenant les gradients exacts du modèle (utilisé pour décrire le comportement de l'éolienne). Les résultats présentés explorent le potentiel méthodologique proposé. La première conception optimale réalisée minimise le coût du matériau actif du générateur, ce qui présente une réduction significative des coûts par rapport à un générateur non optimal. Ensuite, la contradiction entre le coût du générateur et son efficacité est analysée et l'importance d'inclure la production d'énergie éolienne dans la conception du générateur devient évidente. En utilisant l'énergie éolienne estimée générée par l'éolienne, le générateur avec un bénéfice net maximal (égal au produit de l'énergie éolienne moins le coût du générateur) a été obtenu. Ce générateur a un bon rapport entre son coût et sa capacité de produire de l'énergie. Ensuite, des analyses de sensibilité ont été effectuées pour vérifier comment le prix de l'électricité et la vitesse moyenne annuelle du vent influencent la conception. Enfin, deux éoliennes de différents diamètres et différents vitesses nominales du vent ont été utilisées, compte tenu de trois profils de vent distincts. Ces résultats fournissent les générateurs plus adaptés à chaque éolienne appliquée à chaque profil de vent, montrant que la méthodologie de conception proposée a la capacité de faciliter le choix de l'éolienne adéquate à chaque parc éolien.