Comparison of outer-rotor permanent magnet machines for in-wheel drives

This paper quantitatively discuss and compare the emerging outer-rotor PM in-wheel motor drives, which can directly couple with the EV tire rim and remove the traditional mechanical transmission. These new types of in-wheel motor drives include the PM hybrid brushless (PMHB) type, PM memory brushless (PMMB) type, PM magnetic-geared (PMMG) type, and PM vernier brushless (PMVB) type. And all of them are able to produce the high torque output by their distinct features of flux control or flux modulation. Their configurations, in-wheel drive operation principles, and detailed operation performances are given to verify the validity of their in-wheel applications. © 2013 IEEE.published_or_final_versio

A new fault-tolerant flux-reversal doubly-salient magnetless motor drives with four-phase topology

Paper no. YD-014184The proposed fault-tolerant flux-reversal doubly-salient (FT-FRDS) magnetless motor drive consists of armature winding for driving and DC-field winding for field excitation. The purpose of this paper is to investigate two remedial strategies for fault-tolerant operations of the proposed motor drive under short-circuit faults. First, short-circuit phase can be disabled and the short-circuit fault can then be regarded as the open-circuit fault. By reconstructing the healthy armature phases, the reduced torque can be remedied and this is known as the fault-tolerant brushless AC (FT-BLAC) operations. Second, short-circuit fault can also be remedied based on the DC-field regulation alone, and this is known as the fault-tolerant DC-field (FT-DC) operation. These two remedial operations are compared and verified by the finite-element-method (FEM). © 2015 IEEE.postprin

A transverse flux permanent magnet linear generator for hybrid electric vehicles

Article: TD-007358This paper presents a transverse flux permanent magnet (TFPM) linear generator for the free-piston generation application, which not only possessing the merits of the existing TFPM machine, but also providing a simple structure which is essential for power generation with maintenance-free operation. Also, the machine configuration is optimized such that the induced voltage is maximized while the cogging force is minimized. Hence, a 2-phase linear TFPM is resulted, which is well supported by performance analysis.published_or_final_versio

Fault signature of a flux-switching DC-field generator

Paper no. EH-12Flux-switching DC-field (FSDC) machine has the merits of low-cost and flux control ability. Furthermore, this type of machine also possesses the advantage of fault-tolerant capability [1]. However, a few studies have been done on the analyses of fault signatures of this type of machine even though it has two sets of windings [2]. © 2015 IEEE.published_or_final_versio

Design and analysis of a new multitoothed magnetless doubly salient machine

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Mechanical offset for torque ripple reduction for magnetless double-stator doubly-salient machine

Paper no. EQ-07This journal issue contains selected papers from the 2014 IEEE International Magnetics (INTERMAG) ConferenceThis paper implements the new design structure, so-called the mechanical offset (MO) into the double-stator multitoothed swiTChed reluctance (DS-MSR) machine to form the new MO-DS-MSR machine. The major distinction of the MO structure is to purposely mismaTCh the outer and inner rotor teeth with a conjugated angle. With the MO structure, the outer and the inner torque components can be compensated with each other, hence minimizing the resultant torque ripple. By employing the finite element analysis, the characteristics and performances of the proposed machines are analyzed and compared.published_or_final_versio

A high-torque magnetless axial-flux doubly-salient machine for in-wheel direct drive applications

This journal issue contain selected papers from the 2014 IEEE International Magnetics (INTERMAG) ConferencePaper no. FQ-11In this paper, the concept of dc-field excitation is newly incorporated into the axial-flux doubly salient (AF-DS) machine, leading to create the new magnetless AF-DSDC machine. With the external field excitation, the proposed machine not only can enjoy its improved torque density, but also the flux-weakening capability for the wide-speed range operation. With these characteristics, the AF-DSDC is favorable for the in-wheel direct drive application. In particular, the proposed machine is designed and compared based on the requirement of a typical passenger electric vehicle. To have a better illustration, a radial-flux DSDC machine is also designed under the fair environment. The corresponding performances of both machines are analyzed by using the 2-D and 3-D finite element method.published_or_final_versio

Quantitative comparison and analysis of magnetless machines with reluctance topologies

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Magnetic vibration analysis of a new DC-excited multitoothed switched reluctance machine

GQ - Electrical Machines for industrial and automotive applicationsThis journal issue contains selected papers from the 2014 IEEE International Magnetics (INTERMAG) ConferenceThis paper proposes a combined numerical and analytical approach for magnetic vibration analysis of a new dc-excited multitoothed switched reluctance (MSR) machine. First, the machine design is artfully to incorporate the dc-excited winding into the MSR topology, hence breeding a new flux controllable, high-torque, low-torque ripple, and doubly salient magnetless machine. Then, the finiteelement-method is used to calculate the machine force and torque. A series of analytical equations are formulated to calculate the magnetic vibration parameters of the proposed machine. The analysis process and the corresponding results are given to verify the validity of the proposed approach for magnetic vibration analysis of the new machine.published_or_final_versio

A new linear magnetic gear with adjustable gear ratios and its application for direct-drive wave energy extraction

In this paper, a new linear magnetic gear with multiple gear ratios is proposed. Unlike the conventional linear magnetic gears, the proposed one purposely utilizes the aluminum-nickel-cobalt (AlNiCo) permanent magnets (PMs) as the excitation source. Due to the relatively low coercivity, AlNiCo PMs can be magnetized or demagnetized by applying an appropriate DC current pulse into the magnetizing winding. Thus, the pole-pair numbers of PMs on two movers can be varied accordingly so that different gear ratios can be achieved. Firstly, the mathematical modeling of the hysteresis loop of AlNiCo PMs is established. Then, the proposed linear magnetic gear with adjustable gear ratios is presented. Instead of the traditional surface-mounted PM configuration, the proposed machine installs the PMs using the surface-inset and consequent-pole configuration. Hence, the adverse influence during the magnetizing or demagnetizing process can be minimized. Since the magnetizing windings are placed in the movers, no position control is required for the magnetizing or demagnetizing process. By applying finite element analysis, the electromagnetic performances of the proposed linear magnetic gear with adjustable gear ratios are evaluated. Finally, the proposed linear magnetic gear is applied for direct-drive wave energy extraction. Owing to the capability of adjustable gear ratios, the wave energy converter can be operated in resonance with the waves at different sea states so that the maximized power can be captured