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This paper addresses the torque production and losses of concentrated winding permanent magnet motors. These synchronous motors having either semi-closed slots or open slots with two different rotor structures are studied. The rotors have either embedded magnets or surface magnets. Embedded magnet rotors are in some cases easier to manufacture than surface magnet rotors, and therefore, it was in the authors' interest to study and compare these two basic constructions. In open slot concentrated winding motors, it is possible to use prefabricated coils, which leads to low-cost and fast stator winding manufacturing. Hence, this stator type is the most interesting one to be studied. Different slot and pole combinations are considered based on the finite element analysis (Flux2D by Cedrat is employed in the computations). Index Terms--Concentrated winding, embedded magnets, open slots, permanent magnet motor, rotor surface magnets, semi-closed slots.

A numerical analysis of rotor losses in a medium speed direct torque controlled permanent-magnet synchronous motor (PMSM) is presented. The calculation of stator currents at no-load and at rated torque was performed by using a DSP-based emulator, which simulates the performance of a real direct torque controlled PMSM. The emulated stator currents were used in the two-dimensional finite-element method analysis where the rotor losses were calculated. It is shown that in the medium speed direct torque controlled PMSM, the rotor losses are considerably higher when operating at no-load compared to rated torque operation at the same rotation speed. Calculated rotor losses are compared to the measured no-load losses of the direct torque controlled PMSM at 7500 rpm. Index Terms--Eddy currents, finite-element method, permanent-magnet motor, rotor losses.

Optimal design for an axial-flux permanent magnet synchronous generator (AFPMSG) using genetic algorithm (GA) is presented, and the condition for minimum active material cost is deduced. A computer-aided design procedure based on the results of the GA is proposed. In the design procedure the practical and performance characteristics are taken into account as some restrictions for the object function used in the optimization algorithm. A 30-kW AFPMSG with two parallel connected stators and rotor-surface PMs is designed using the developed program, and then 3-D finite-element analyses are carried out to validate the design procedure. [ABSTRACT FROM AUTHOR]