Search

Lead halide perovskites with good optoelectronic properties and high attenuation of high-energy radiation are great candidates for X-ray radiation detectors. Large area, dense, and thick films or w...

In order to improve the accuracy of rotor position estimation for sensorless controlled stator permanent magnet motor, which back electromotive force (EMF) exhibits nonsinusoidal waves, by employing the second order generalized integrator (SOGI), a revised extended state observer is proposed. The estimated position fluctuation errors resulted from both flux spatial harmonics and the inverter nonlinearities are analyzed. The SOGI is utilized to eliminate the multiple harmonics and extract the fundamental of the estimated back EMF. In addition, the software quadrature phase-locked loop with back-EMF normalization is utilized to calculate the rotor position in order to eliminate the influence of the back-EMF magnitude change at different speed. Finally, the comparison experimental results verify the effectiveness of the proposed method.

The traditional bearingless permanent magnet synchronous motor has complex decoupling control problems. To overcome the drawbacks above, a novel hybrid permanent magnet type bearingless motor (HPMTBM) is proposed in this paper, which has integrated the merits of hybrid excitation permanent magnet motor and magnetic bearings. The main advantages of this HPMTBM are the simple control mechanism and the low power consumption. First, the principle and theoretical background of this motor are introduced. Then, the mathematical models of radial suspension force and torque are established using Maxwell stress tensor method, and air-gap magnetic fields, radial suspension forces are calculated by finite-element analysis. Finally, the prototype motor is designed and constructed. The radial suspension forces and rotor radial displacements are tested. The simulation and experimental results show the feasibility of the proposed HPMTBM.

This paper presents the design and evaluation of an Outer-Rotor Permanent-Magnet Flux-Switching (ORPM-FS) machine. A brief overview of relevant operating principles is given first. To realize the design objectives of high-torque capability, low-torque ripple, high efficiency, and high reliability, a new multilevel design optimization method is proposed to conduct the multi-objectives optimization. Finally, a prototype machine is built to verify the validity of the proposed design method and machine performance.

This paper introduces a high torque density permanent magnet (PM) machine for direct driving application, which adopts two V-shape tangential alternately magnetizing PM pieces in one stator pole in the brushless PM machine. The machine is optimized and the performance is compared with different PM dimensions and validated by experiment. The results indicate that the proposed machine benefits from reduced PM usage, improved torque density, and torque per magnetic volume, compared with the conventional flux-switching permanent magnet (FSPM) machine.

The flux-switching permanent-magnet double-rotor machine (FSPM-DRM) used for hybrid electric vehicles (HEVs) has attracted considerable attention due to the compact structure. This paper aims to make an accurate prediction of the performances in the FSPM-DRM. The machine topology is firstly introduced. By using the finite element method (FEM), the electromagnetic performances considering losses and temperature rise are analyzed. Finally, the PM demagnetization of the FSPM-DRM machine is studied, which indicates that the partial demagnetization will occur in the PMs. And the FEM results are verified by the tests on the prototype machine.

A lumped-parameter (LP) thermal model is presented for a flux-switching permanent-magnet double-rotor machine (FSPM-DRM) used for hybrid electric vehicles (HEVs), which has attracted attention due to the compact structure. The model provides the steady-state thermal solution to derive the temperatures at different parts of the machine, including the temperatures in the stator windings and the temperatures of the magnets. Temperature-dependent thermal properties of the materials used in the machine construction as well as the stator resistance and consequently copper losses require temperature update in accurate design of the machine. Therefore, an iterative coupled electromagnetic and thermal design program is proposed in this paper. A l-kW/l-kW FSPM-DRM prototype machine is designed and manufactured. Tests performed on the designed machine verify that the defined thermal resistance network has a high ability to predict the nodal temperatures accurately.

In this paper, the structure and operation principle of a slice hybrid magnetic bearing (HMB) with two radial air-gaps are analyzed, and the mathematical model of radial suspension force is deduced. Then, the magnetic paths are analyzed, and the radial suspension force is calculated by finite element method. Finally, the experimental prototype HMB is designed and constructed, where waveforms of stable suspension and antiinterference experiment are tested. The theory analysis, simulation and experimental results have shown that the proposed slice HMB can achieve stable suspension.

In this paper, a novel bearingless permanent magnet slice motor is introduced. Both stator and rotor are made of double slice structure. An axial magnetized permanent magnet ring is placed in the stator core. Biased flux forms the closed path through the stator core, air gap, rotor core. The suspension force is produced by the interaction between the biased flux and suspension control flux. The motor structure and operation principle are analyzed, and the mathematical models of radial suspension forces are deduced using the equivalent magnetic circuit method. The 3D finite element analysis is used to verify the structure and mathematical models.