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This paper proposes an electromagnet-assisted ferrite magnet motor (EMaFM) with a double air-gap structure. To confirm the principle and validity of the proposed EMaFM, a prototype machine was designed and fabricated. Moreover, the electromagnetic performance of the prototype machine was simulated using a finite-element analysis (FEA) and was supported by experiments. The proposed EMaFM has field regulation capability while utilizing the ferrite magnets. From the FEA and experimental results, it was found that the torque can be controlled widely by the armature current or field current. [ABSTRACT FROM AUTHOR]

In this paper, the core losses that occur in a 4-kVA flux-modulating synchronous machine (SM) (FMSM) are investigated using 2-D finite-element analysis, and the results are supported by experiments. A method for reducing the core losses is also presented. The FMSM is a new type of multipole SM in which the stator field magnetomotive force is modulated by the air-gap permeance to generate the rotating field. A 2pa-pole three-phase armature winding and a 2pf-pole field winding are centrally wound around individual stator teeth, and a reluctance rotor with 2pr\ (= pa + pf) saliencies is used to provide a magnetic coupling between these windings. As a result of the investigation, it was found that, although the core losses occur in the rotor as well as in the stator, the rotor core loss can be effectively reduced by decreasing the height of the rotor poles. [ABSTRACT FROM AUTHOR]

This paper presents a new type of multipole synchronous machine (SM) in which 2pa-pole armature and 2pf-pole field windings are centrally wound around individual stator teeth. The proposed machine operates as a (2pa + 2pf)-pole SM by providing a magnetic coupling between the armature and field windings through a 2pr-pole reluctance rotor. A 4-kVA (32 + 48)-pole prototype machine was designed and built to validate the principle of this structure. Performance characteristics of the prototype machine were simulated using 2-D finite-element analysis (FEA) and were supported by experiments. In addition, the effects of the rotor pole shape on the performance characteristics were studied through 2-D FEA simulations. The results presented provide guidelines for the optimum design of the proposed machine. [ABSTRACT FROM PUBLISHER]

The characteristic improvements of salient-pole synchronous generators by inserting additional permanent magnets are investigated from both results of finite-element analyses and experiments. First, the assist effects of the magnets in a megavoltampere-class generator are analyzed by the finite-element method. It is clarified that the additional permanent magnets have the effects of reducing magnetic saturation at the rotor-pole bodies, as well as the effects of increasing the direct flux linkage of armature windings. It is also clarified that the output of the generator can be increased by more than 20% by inserting the magnets without any increase in total machine size and decrease in efficiency. Finally, the characteristic improvements are validated by the experiment of a small prototype generator. The experimental and calculated results are found to be in good agreement. [ABSTRACT FROM PUBLISHER]

This paper presents the modeling and steadystate performance of a novel dual-winding reluctance generator (DWRG) that uses a multiple-barrier (MB) rotor. A simple mathematical model was developed, and the effects of external parameters (speed, field current, and load) on the steady-state performance were analyzed. Experimental results conducted on a prototype machine were also provided to justify the theoretical approach and performance calculations. The developed model takes into account the magnetic saturation and core loss and enables a quantitative prediction of load characteristics from the no-load test data. [ABSTRACT FROM AUTHOR]