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In this paper, the performance of air-cored (ironless) stator axial flux permanent magnet machines with different types of concentrated-coil nonoverlapping windings is evaluated. The evaluation is based on theoretical analysis and is confirmed by finite-element analysis and measurements. It is shown that concentrated-coil winding machines can have a similar performance as that of normal overlapping winding machines using less copper. Index Terms--Air cored, axial flux, concentrated winding, permanent magnet (PM).

In this paper, a thermofluid model combining a lumped parameter heat transfer model and an air-flow model of a typical axial-field permanent-magnet (AFPM) machine is developed. The accuracy and consistency of the derived model are assessed by comparing the calculated flow rate and temperature values of a prototype machine with the measured ones. The developed thermofluid model is shown to perform thermal calculations with reasonable accuracy. Index Terms--Air cooling, axial field, heat transfer, permanent-magnet machine, thermal modeling.

This paper describes a hybrid method for calculating the performance of a coreless stator axial flux permanent-magnet (AFPM) generator. The method uses a combination of finite-element analysis and theoretical analysis. The method is then incorporated into a multidimensional optimization procedure to optimally design a large power coreless stator AFPM generator. The measured performance of the manufactured prototype compares favorably with the predicted results. The design approach can be applied successfully to optimize the design of the coreless stator AFPM machine. Index Terms--Axial flux, design, finite-element methods, optimization methods, permanent-magnet generator.

This paper presents a hybrid method for the calculation of eddy current loss in coreless stator axial field permanent-magnet (AFPM) machines. The method combines the use of two-dimensional finite element (FE) field analysis and the closed-form eddy loss formula. To account for three-dimensional field effects in an AFPM machine, a multilayer and multislice modeling technique has been devised. Experimental tests are carried out to validate the method. It is shown that the proposed method predicts the eddy current losses of a coreless stator AFPM machine with high accuracy. Index Terms--Axial field, eddy currents, finite-element (FE) method, permanent-magnet (PM) machine.