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A design method and load evaluation system for a single-phase linear permanent magnet generator (SPLPMG) for Stirling engines are proposed. The generator was designed considering the short stroke of the system and the characteristics of high-speed reciprocating motion. The accuracy of the 2-D finite-element method (FEM) was improved by considering the outer core and inner core split lamination characteristics. A test rig for evaluating the SPLPMG was fabricated. The evaluation system consisted of a crankshaft that converted the rotational motion into reciprocating motion, so that the linear generator could be evaluated as a rotational power source. The load test was carried out according to the operational frequency of the generator. An SPLPMG output of 3 kW was obtained, and the FEM analysis results and evaluation results were similar.

Single-phase squirrel-cage induction motors are widely used in household and industrial electronics, because of their simplicity, low cost, and ruggedness. The cage rotor of the induction motor is produced using laminated electrical steel sheets subjected to die-casting processes with various manufacturing parameters. However, the die-casting process generates pores in the cage-rotor end-ring. These pores have a significant effect on the motor properties, which cannot be accurately analyzed. In this paper, squirrel-cage rotors with different porosities were prepared by varying the die-casting process. Then, the end-ring porosity was accurately analyzed using X-ray computed tomography. The inter-bar resistance of the squirrel-cage rotor was calculated from the end-ring porosity rate. Finite-element analysis (FEA) was used to predict the effects of porosity on the motor performance. Finally, the motor was tested, and the measurements were compared with the FEA-predicted results. The analytical and experimental results obtained for a 1.5 kW single-phase squirrel-cage induction motor were very similar, when the end-ring porosity was included in the analysis.

This paper presents the torque analysis and measurements of cylindrical air-gap synchronous permanent magnet couplings based on analytical magnetic field calculations. Employing a magnetic vector potential and a 2-D analytical model with two polar coordinate systems, we obtain the magnetic fields produced by permanent magnets. Then, the analytical torque solutions are derived using these magnetic field solutions and a Maxwell stress tensor method. The analytical results are validated by nonlinear 2-D and 3-D finite element results. Finally, torque measurements are presented to show the effectiveness of the analysis.

While axial flux permanent magnet (AFPM) machines are manufactured, their wrong assembly can be possible, such as misaligned PM rotor position of double-sided machine. Once the machines are assembled, detecting the misaligned rotor is hard, so the designers are required to have deep insight in its related and unexpected characteristics to prevent them focusing on other possible errors. Therefore, this paper deals with the characteristic analysis on the influence of the misaligned rotor position of double-sided AFPM machine and its experimental verification. In general, the AFPM machines have been analyzed by 3-D finite-element method (3-D FEM) due to their structural features, but it requires very long analysis time to consider various factors. For this reason, analytical approach is presented in order to consider all the cases of the misaligned rotor positions, and it is confirmed to be practical to detect the positions and to reduce analysis time with high reliability. With the analytical approach, the misaligned rotor position characteristics, such as back-emf and its total harmonic distortion are analyzed. Furthermore, all the analysis results are validated by 3-D FEM results and experimental verification.

This paper reports on the design and dynamic analysis of magnetically levitated electromagnets with a low-resolution position sensor. On the basis of the equivalent magnetic circuit method and a 3-D finite element analysis model, an initial and detailed design of an electromagnet was realized. The validity of the design was confirmed analytically and experimentally. Then, by employing a closed-loop proportional-integral-derivative control algorithm, the dynamic behavior of the electromagnets was also investigated experimentally. In particular, by employing low-pass filters for a low-resolution position sensor and an acceleration sensor, the air gap could be precisely controlled at low cost.

This paper presents a comparative analysis of the characteristics of high-speed permanent magnet synchronous machines (PMSMs) with diametrically magnetized rotors under different construction conditions of the rotor magnetic circuit. An analytical method is adopted to predict the magnetic field distribution and to calculate the electrical parameters by using the transfer relations based on a two-dimensional model in a polar coordinate system. In addition, three types of PMSMs with diametrically magnetized permanent magnets are proposed in this work. The electrical parameters are estimated and the magnetic field distribution is analyzed for those models, and these results are compared with those obtained using the finite element method; the two sets of results are found to be in good agreement. On the basis of the analysis results, a real model manufactured and the validity of our results is demonstrated by performing suitable experiments.

This paper deals with the magnet pole shape design of permanent magnet machines for the minimization of torque ripple based on electromagnetic field theory. On the basis of a magnetic vector potential and a two-dimensional (2-D) polar system, analytical solutions for flux density due to permanent magnet (PM) and current are obtained. In particular, the analytical solutions for mathematical expressions of magnets with different circumferential thicknesses can be solved by introducing improved magnetization modeling techniques, resulting in accurate calculations of electromagnetic torque. The analytical results are validated extensively by nonlinear finite element method (FEM). Test results such as back-emf measurements are also given to confirm the analyses. Finally, on the basis of derived analytical solutions, a reduction of torque ripple can be achieved.

This paper deals with the thrust calculations and the measurements of a cylindrical linear oscillatory actuator (LOA) using transfer relations theorem (TRT), namely, Melcher's methodology. Using transfer relations derived in terms of a magnetic vector potential and a two- dimensional (2-D) cylindrical coordinate system, this paper derives analytical solutions for the magnetic vector potential, magnetic fields due to permanent magnets (PMs), and stator winding currents and the thrust. The analytical results are validated by nonlinear finite element (FE) analyses. In particular, test results such as thrust and back-EMF (electromotive force) measurements are given to confirm the analysis.

This paper deals with design and analysis of the moving-magnet linear actuator with cylindrical Halbach array. On the basis of two-dimensional (2-D) finite-element analysis, this paper predicts thrust characteristics according to design parameters such as magnet height, air-gap length, coil thickness, and pole number. Then, we manufactured equipment made on an experimental basis of moving-magnet linear actuator with cylindrical Halbach array by employing parameters obtained from design results. Finally, this paper presents test results such as thrust measurements, which are given to confirm the finite-element analysis, according to load current and mover position.

In this presentation, the magnetic properties and electronic structure of Cr incorporated SiC(100) surface, including the surface formation energy and the surface electronic structure, was extensively investigated using ab initio calculations. the surfaces of p(2times1) and c(4times2)-AUDD were employed to simulate the Si-terminated SiC(100) surface, and the c(2times2) was prepared to calculate the C-terminated surface. The total magnetic moment and the magnetization energy were obtained by the spin-polarized calculation for one Cr atom in the SiC(100) surface supercell. Due to the surface effect of SiC(100), the total magnetic moment of SiC(100):Cr-p(2times1) was found to be increased. The origin of the surface magnetism will be discussed in terms of the density of states and the wave function characteristics around the Fermi level.

This paper deals with the dynamic characteristic analysis and experiments of moving-magnet linear actuator with cylindrical Halbach array. On the basis of two-dimensional analytical solutions and experiments, control parameters are obtained. Then, a dynamic simulation algorithm is established from a voltage and motion equation. Finally, for various values of frequency, dynamic simulation results for characteristics of voltage, current, and displacement of moving-magnet linear actuator are presented and confirmed through the experiments.

This paper deals with the comparison of two types of permanent magnet high-speed machines. Specifically, the effect of permanent magnet magnetization pattern on the rotor losses is investigated. On the basis of analytical field analysis and two-dimensional (2-D) finite-element method, this paper predicts the flux harmonics and rotor losses under no-load condition. It is shown that the Halbach magnetization is superior to parallel magnetization in terms of producing rotor losses.

This paper deals with analysis and experiments of moving-magnet linear actuators with cylindrical Halbach arrays. On the basis of analytical two-dimensional field solutions, this paper predicts magnetic fields, thrust, flux linkage, and back electromagnetic fluctuation. The results are validated extensively by comparison with finite element analysis. Test results such as thrust measurements are also given to confirm the analysis.

This paper deals with temperature performance of induction heating roll with or without heat pipes. The focus of this paper is to improve nonuniformity of the outer surface temperature of the roll by inserting heat pipes with very high thermal conductivity. In our work, the coupled magneto-thermal finite-element analysis considering skin effect is employed for evaluating the surface temperature. The predicted results are verified with experimental data.

This paper deals with the application of cylindrical Halbach array to a permanent magnet motor capable of producing pure rotary motion, pure linear motion, or helical motion. The proposed motor consists of an exterior polar Halbach quadrupole array for a rotary motion and an interior cylindrical Halbach dipole array for a linear one. The two-dimensional finite-element method is employed for predicting the effect of design parameters of the machine.

Summary form only given. The eddy current brake system ofa high-speed railway has been developed because of the mechanical adhesion limit. It have been used in magnetic levitation applications and in high velocity trains in order to avoid the abrasion of a mechanical disc brake. The eddy current brake system with permanent magnet has a simple structure, rugged characteristics and low cost because of no control and power system. In this paper, the characteristics analysis of an eddy current brake system using the linear Halbach array are analyzed by the analytical method and FEM.

Summary form only given. This paper presents the design criteria for the detent force reduction of the permanent magnet linear synchronous motor (PMLSM) with Halbach array. There are three approaches to improve the power efficiency of short PM pole-type LSMs: (1) the comparison of the magnetic field and forces of two types of PMLSM-a PMLSM with a Halbach array (HA-PMLSM) and a PMLSM with a conventional array (CA-PMLSM); (2) the determination of PM length/slot pitch of the two types with minimum detent force; and (3) the comparison of the force performance of two types with the minimum detent force.

Summary form only given. Permanent magnet linear synchronous motors (PMLSMs) have been developed for factory automation, reciprocating servo systems, conveyance systems, transportation applications, wafer steppers, etc. In the authors' work, an air-cored film coil is used for their primary winding. Such a winding is compatible with the servo, miniature and precision motion-controlled linear machines. However, air-cored PMLSMs have lower thrust density than cored PMLSM. Fortunately, the Halbach array improves the power efficiency of electromagnetic machines. On the basis of an analytical technique, FEA and experiments, this paper deals with the design guidelines and analysis of two types of PMLSM for the application of servo and miniature linear machines.