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This paper proposes an adjustable-speed permanent magnet eddy-current coupling with a non-rotary mechanical flux adjuster (MFA) to regulate the speeds of large pump and fan for energy saving. The slip speed of the proposed coupling can be adjusted by shifting MFA along the axial direction. The structural feature and operation principle of the coupling are illustrated and addressed. A magnetic equivalent circuit model is established for analyzing the electromagnetic characteristics of the coupling efficiently. The air-gap magnetic fields, eddy-current densities, and torque–slip characteristics are investigated under different shifting distances of MFA, which reveals the fairly good torque regulation effects. The torque regulation range reaches to about 90% of the maximum torque, which indicates that the coupling can achieve a large speed regulation range by using the relatively simple approach. [ABSTRACT FROM AUTHOR]

This paper proposes a new hybrid magnet (HM) dual-stator vernier machine (DSVM) with flux-reversal (FR) magnet arrangement, in which NdFeB and ferrite magnets are reversely mounted on tooth tips of outer and inner stators, respectively. The hybrid dual excitation topology enhances the magnetic fields of inner and outer air-gaps, which are modulated by the rotor composed of iron poles. The proposed topology, operating principle, and design consideration are described. The merits of the proposed HM-FRDSVM are verified when compared to the same FRDSVMs with dual NdFeB magnet excitation and with dual ferrite magnet excitation and the conventional dual stator synchronous permanent magnet machine. The two-dimensional finite element analysis results show that the proposed machine has high torque cost performance with low torque ripple and low cogging torque that are desirable for large telescope drive application. [ABSTRACT FROM AUTHOR]

This paper proposes a new topology of a variable-flux pole-changing permanent magnet (PM) memory machine. The fractional-slot concentrated windings are employed in the stator side, which can increase the utilization ratio of winding under different pole modes. The neodymium–iron–boron PM poles and aluminum–nickel–cobalt (AlNiCo) PM poles are hybridized in the rotor side. The proposed machine features the capability of its pole number to switch back and forth between six poles and two poles through changing the magnetization directions of AlNiCo PMs via the stator winding. Besides, the air gap flux can be flexibly adjusted by varying the amplitudes of magnetization current pulses. The topology and design principle of the machine are described in detail, and the electromagnetic characteristics, including magnetic field distributions, air-gap flux density, as well as back electromotive force (EMF), in different operation modes are computed using a finite-element method. Due to the existence of the fifth harmonic component of back EMF, the torque quality is improved through injecting the fifth harmonic current under different magnetized levels of AlNiCo PMs. Besides, the field regulation capabilities in both the pole modes are analyzed. [ABSTRACT FROM AUTHOR]