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Owing to the definite merits of high-efficiency and high-power density, the permanent-magnet (PM) brushless machines have been dominating the high-performance industrial applications. However, the problems of high PM material cost, fluctuating supply of rare-Earth materials and ineffective PM flux control have hindered the widespread applications of the PM brushless machines. In recent years, many attentions have been shifted to the magnetless candidates, while the focuses are mainly placed on the classical candidates. In this study, an overview of magnetless brushless machines including both the classical and advanced types is presented, with emphasis on their machine topologies, features and performances. In addition, the upcoming trend of these machines is reviewed and discussed. [ABSTRACT FROM AUTHOR]

This paper presents and implements the power loss analysis of a new kind of permanent magnet hybrid brushless (PMHB) machines with and without using high-temperature superconductor (HTS) field windings. The circuit-field-torque time-stepping finite element method together with experiential equations is developed to perform power loss analysis of the PMHB machine. Experimentation is carried out to verify the proposed loss analysis. [ABSTRACT FROM AUTHOR]

This paper proposes a new efficiency optimization approach for a new kind of permanent-magnet hybrid brushless (PMHB) machine. The key is to propose the self-searching control (SSC) for the PMHB machine in such a .way that the input power at the given load and speed can be progressively minimized by tuning the dc field current. A loss analysis of the machine is given to justify the use of dc field current as the control parameter. Detailed experimental results confirm that the proposed approach can effectively accomplish the desired efficiency optimization. [ABSTRACT FROM AUTHOR]

This paper presents a hybrid excited doubly salient (HEDS) machine, which can be used as the integrated starter-generator (ISG) for modern automobile and hybrid electric vehicles (HEVs). The key of the proposed machine is to incorporate both direct current (dc) field windings and permanent magnets (PMs) in the stator, hence, offering a compact arrangement of hybrid field excitations, while the rotor is simply composed of salient poles without windings or PMs. The air-gap flux can be strengthened or weakened with a reasonable dc field current so that the electromagnetic torque and induced electromotive force (EMF) can be effectively regulated. To predict the electromagnetic performances of the machine more accurately, a new transient cosimulation approach considering indirect field-circuit coupling is proposed. Experimental results on a prototype machine have been given to verify the technique. The method is not only more efficient and flexible, but also more accurate and stable, which can also be used in analyzing other electric machine and drive systems. [ABSTRACT FROM AUTHOR]