No abstract

High-speed axial-flux generators (HSAFGs) with coreless stators are regarded as high-power-density, small-size, high-efficiency machines for use in distributed power generation systems (as microturbines). This paper presents a modelling procedure for such generators with details. The ratio of inner to outer diameter (λ) in axial-flux machines is considered in the same way that the ratio of length to diameter is considered in radial-flux (conventional) machines. The optimized λ is determined for an HSAFG with three rotors and two stators by careful consideration of the output voltage and efficiency variations versus λ. It is concluded that λ plays an important role in the HSAFG and requires careful attention when the machine is designed.Les générateursà haute vitesse età flux axial (HSAFG) avec stators sans noyau sont considérés comme des machines de haute densité de puissance, de petite taille età haut rendement. Ils sont utilisés dans des systèmes de génération d'énergie distribuée (comme les microturbines). Ce document présente une procédure de modélisation pour ces générateurs avec les détails. Le rapport entre le diamètre intérieur et extérieur (λ) en machinesà flux axial est considéré, tout comme le rapport de la longueur et le diamètre est pris en compte dans les machinesà flux radial (classique). Le λ optimisé est déterminé pour un HSAFG de trois rotors et deux stators par un examen soigneux de la tension de sortie et des variations de l'efficacité en comparaisonà λ. Il est conclu que λ joue un rôle important dans le HSAFG et requiert une attention particulière lors de la conception de la machine.

No abstract

Problem Statement: Axial flux permanent magnet machines are regarded as compact high efficiency generators for micro-turbines employed in the distributed power generation systems. Highspeed rotor of the generator causes some designing and modeling problems. Sensitivity analysis tasks of the machine parameters are difficult and completely different in comparison with the problems associated with conventional machines. Approach: This article presents a modeling procedure with some details for performance predictions of High-Speed Axial Flux Generator (HSAFG). The FEM results are employed to validate the proposed model. Proper values of inner diameter to outer diameter ratio, plus back iron thickness of two rotor discs located in two ends are serious design problem for a HSAFG. Results: Impacts of these two parameters on the performance characteristics of a HSAFG are investigated in this paper. Their optimum values are determined for the machine by somewhat precise considerations of the output voltage and efficiency. Conclusions/Recommendations: It has been found out that the optimum performance of HSAFG regarding the voltage and efficiency is achieved by the value of inner to outer diameter ratio sited between 0.5-0.65. Moreover, the thickness of the rotor back iron can be designed by trial method to produce sufficient air gap flux and resultant terminal voltage. Adding extra back iron would just increase the rotor inertia with no benefit.

No abstract