Search

This paper presents a novel consequent-pole hybrid brushless wound-rotor synchronous machine (CPH-BL-WRSM). The proposed machine employs permanent magnets (PMs) on the alternate poles of the salient pole rotor, which has considerably less magnet usage compared to the regular (PM) assisted synchronous machine. The proposed CPH-BL-WRSM offered the advantages of high starting torque, high torque density, and better performance under full-load conditions. The BL operation for the proposed machine is achieved by generating a composite magneto motive force (MMF) with a fundamental component and sub-harmonic component. The sub-harmonic component of the stator MMF is used for BL excitation of the rotor. The finite-element method was used to analyze the performance of the CPH-BL-WRSM in comparison with the performance of the existing BL-WRSM and regular PM-assisted BL-WRSM. Finally, a prototype of the CPH-BL-WRSM was manufactured and the experiment was conducted to demonstrate the performance of the proposed CPH-BL-WRSM. [ABSTRACT FROM AUTHOR]

In the preliminary design of the variable flux memory motor (VFMM), it is essential to examine the magnetization characteristics of the permanent magnet (PM) according to different direct-axis current pulses, which requires numerous parametric studies. In this paper, we propose a non-linear PM load-line model for concentrated winding surface-mounted PM VFMMs by making use of the magnetic equivalent circuit method, which is valid for investigating the PM magnetization state considering non-linear magnetic characteristics. The proposed method is validated through a comparison with the results of non-linear finite-element analysis. [ABSTRACT FROM AUTHOR]

The transverse-flux linear switched-flux permanent magnet machine is investigated by 3-D finite-element analysis in this paper. The topology of the machine, as well as the machine operation principle, is introduced first. In order to improve the thrust force performance of the machine, two aspects are analyzed. One is the average thrust force, which is maximized by optimizing the mover stack length and the stator pole stack length. Not only does the average thrust force increase, but the force ripple slightly decreases as well. The other side is further lowering the force ripple. The segment group shift method is introduced and employed. After using this method, the force ripple has been reduced to an acceptable value, though the average thrust force will be slightly reduced. The analysis is the guidance for better understanding this novel machine. [ABSTRACT FROM AUTHOR]

In this paper, three partitioned-stator (PS) machines, namely the PS flux-switching permanent-magnet (PS-FSPM) machine, the PS-FS hybrid-excitation machine, and the flux adjuster PS-FSPM (FA-PS-FSPM) machine are proposed for the hybrid electric vehicles (HEVs). Owing to the installation of additional inner-stators, all three proposed machines can offer satisfactory power and torque densities. In particular, the FA-PS-FSPM machine artfully utilizes its inner space to accommodate the mechanical FAs, such that outstanding flux-weakening capability for wide-speed range operation can be achieved. To verify the proposed concept, the established machines are purposely compared with the profound Prius HEV machine based on finite-element method. [ABSTRACT FROM AUTHOR]

A dual-stator hybrid-excited switched-flux (DS-HESF) machine, which is based on the conventional SF permanent magnet machine but employs a secondary stator to accommodate the field windings, is proposed in this paper. The DS-HESF machine inherits the robust rotor and benefits from a better space utilization. The topology and operating principle of the proposed machine are introduced in detail. Based on the 2-D finite-element analysis, the comparison between the DS-HESF machines having different rotor pole numbers is carried out, accompanied with a conventional HESF machine as a baseline. The results reveal that the DS-HESF machines exhibit not only higher torque density but also a better flux regulation capability. The prototype is manufactured and tested to validate the predictions. [ABSTRACT FROM PUBLISHER]

This paper proposes a new four-phase flux-reversal dc-field (FRDC) machine for the wind power generation applications. The key distinction of the proposed generator is to artfully design its stator pole and winding arrangement in a way imitating the permanent-magnet (PM) configurations, which the profound FRPM machine has. Hence, the proposed FRDC generator can provide the bipolar flux-linkage patterns and achieve performances similar to that of the high-quality FRPM generators. The proposed generator can regulate its controllable dc-field winding to vary its flux density effectively. Thus, it can achieve the constant-output-voltage characteristics at different situations in order to extend the battery life and to protect the power grid system. Without installation of any high-cost PM materials, the proposed magnetless FRDC generator can achieve better cost-effectiveness than its PM counterparts. The key performances of the proposed wind power generator are thoughtfully analyzed by the finite-element method, while the experimental prototype is also setup for verifications. [ABSTRACT FROM AUTHOR]

This paper focuses on the design and the analysis of an ultrahigh speed axial-flux permanent magnet (AFPM) machine for an aerospace flywheel energy storage system. The superiority of the proposed AFPM machine is the material-efficient PM shape, which contributes to obtain a sinusoidal back electromotive force (back EMF) and, hence, reduces the torque pulsations of the machine such as torque ripple. The harmonics present in back EMF have a large influence on iron loss and torque pulsations, which are always unacceptable in the applications involving the speed as high as 1 000 000 r/min. Analytical modeling is first performed to determine the PM shape for the proposed models. Then, the advantages of the proposed models are verified by comparing with the basic model with the conventional ring-shaped PMs using the 3-D finite-element method. The results show that the proposed models have a nearly ideal sinusoidal back-EMF waveform that significantly reduces the torque ripples compared with the basic model. [ABSTRACT FROM AUTHOR]

This paper investigates an original solution that can be used in the design of axial-flux permanent-magnet (AFPM) machines whenever a constrained shaft height requirement penalizes a standard design. A machine is tailored for electrical traction, but the ideas that are set forth are valid for any application with a constrained shaft height. Two design solutions that comply with a constrained shaft height are investigated, i.e., a standard Torus AFPM machine and an asymmetrically wound Torus machine, which is named “Ω AFPM” due to the shape of the stator winding. It is shown that the Ω AFPM machine has lower losses and higher efficiency. Finite-element simulations and experimental tests on a full-scale prototype confirm the validity of the proposed solution. [ABSTRACT FROM PUBLISHER]

Brushless dc coreless electric machines with double-rotor and single-stator configuration have very low losses, since the return path of the magnetic flux rotates with the permanent magnets. The eddy-current loss in the stator is additionally very small due to the lack of iron, making it ideal for kinetic energy storage. This paper presents a design for self-bearing rotor suspension, achieved by placing the stator windings skewed on a conical surface. A mathematical analysis of the force from a skewed winding confined to the surface of a cone was found. The parametric analytical expressions of the magnitude and direction of force and torque were verified by finite-element method simulations for one specific geometry. A dynamic model using proportional-integral–differential control was implemented in MATLAB/Simulink, and the currents needed for the self-bearing effect were found by solving an underdetermined system of linear equations. External forces, calculated from acceleration measurements from a bus in urban traffic, were added to simulate the dynamic environment of an electrical vehicle. [ABSTRACT FROM AUTHOR]

A novel stator hybrid-excited, parallel flux path, synchronous machine of doubly salient topology is proposed. It has the novel features of: 1) hybrid dc field and permanent magnet (PM) excitation in the stator; 2) magnets placed in the slots between adjacent salient stator poles; and 3) the magnetic poles of PMs arranged, such that the flux premagnetizes the stator, but it is in a direction to oppose the dc excitation flux. The electromagnetic characteristics of the machine are analyzed on open-circuit and load. Since the new machine topology is developed from the variable-flux machine (VFM), a comparison of their electromagnetic torque and machine losses is conducted. The average electromagnetic torque of the hybrid-excited machine can be increased by 18% for fixed copper loss in comparison with the VFM due to the reduction of magnetic saturation in the stator. It is also shown that at high temperatures some risk of PM demagnetization exists when excited with dc and armature currents due to fringing flux that exists between the stator and the rotor poles. However, this affects only a very small area of the PMs. The performance of the hybrid-excited machine is predicted by a 2-D finite-element analysis and experimentally validated. [ABSTRACT FROM AUTHOR]