As a kind of traction device, interior permanent-magnet synchronous machines (IPMSMs) are widely used in modern electric vehicles. This paper performs a design and comparative study of IPMSMs with different rotor topologies (spoke-type PMs, tangential-type PMs, U-shape PMs, and V-shape PMs). The research results indicate that the IPMSM with V-shape PMs is more satisfying with comprehensive consideration. Furthermore, the IPMSM with V-shape PMs is investigated in detail. The influences of geometrical parameters (magnetic bridge and angle between the two V-shape PMs under each pole, etc.) on the performances of V-shape motor are evaluated based on finite-element method (FEM). For accurate research, the effects of saturation, cross-magnetization, and the change in PM flux linkage on d - and q -axis inductances are considered. The back-electromotive force (EMF), flux leakage coefficient, average torque, torque ripple, cogging torque, power per unit volume, power factor, and flux-weakening ability are investigated, respectively. The experimental results verify the validity and accuracy of the process presented in this paper.

Research on the Performances and Parameters of Interior PMSM Used for Electric Vehicles

Cogging torque in permanent-magnet machines causes torque and speed ripples, as well as acoustic noise and vibration, especially in low speed and direct drive applications. In this paper, a general analytical expression for cogging torque is derived by the energy method and the Fourier series analysis, based on the air gap permeance and the flux density distribution in an equivalent slotless machine. The optimal design parameters, such as slot number and pole number combination, skewing, pole-arc to pole-pitch ratio, and slot opening, are derived analytically to minimize the cogging torque. Finally, the finite-element analysis is adopted to verify the correctness of analytical methods.

Analytical Methods for Minimizing Cogging Torque in Permanent-Magnet Machines

Fermented foods and beverages possess various nutritional and therapeutic properties. Lactic acid bacteria (LAB) play a major role in determining the positive health effects of fermented milks and related products. The L. acidophilus and Bifidobacteria spp are known for their use in probiotic dairy foods. Cultured products sold with any claim of health benefits should meet the criteria of suggested minimum number of more than 10⁶ cfu/g at the time of consumption. Yoghurt is redefined as a probiotic carrier food. Several food powders like yoghurt powder and curd (dahi) powder are manufactured taking into consideration the number of organisms surviving in the product after drying. Such foods, beverages and powders are highly acceptable to consumers because of their flavor and aroma and high nutritive value. Antitumor activity is associated with the cell wall of starter bacteria and so the activity remains even after drying. Other health benefits of fermented milks include prevention of gastrointestinal infections, reduction of serum cholesterol levels and antimutagenic activity. The fermented products are recommended for consumption by lactose intolerant individuals and patients suffering from atherosclerosis. The formulation of fermented dietetic preparations and special products is an expanding research area. The health benefits, the technology of production of fermented milks and the kinetics of lactic acid fermentation in dairy products are reviewed here.

Fermented Milks and Milk Products as Functional Foods—A Review

Topology and Selection Definitions, Geometry, and Thrust Generation Linear Synchronous Motor Topologies Calculation of Forces Linear Motion Selection of Linear Motors Materials and Construction Materials Laminated Ferromagnetic Cores Permanent Magnets Conductors Principles of Superconductivity Laminated Stacks Armature Windings of Slotted Cores Slotless Armature Systems Electromagnetic Excitation Systems Superconducting Excitation Systems Hybrid Linear Stepping Motors Theory of Linear Synchronous Motors Permanent Magnet Synchronous Motors Motors with Superconducting Excitation Coils Variable Reluctance Motors Permanent Magnet Hybrid Motors Motion Control Control of AC Motors EMF and Thrust of PM Synchronous and Brushless Motors Dynamic Model of a PM Motor Thrust and Speed Control of PM Motors Control of Hybrid Stepping Motors Precision Linear Positioning Sensors Linear Optical Sensors Linear magnetic Encoders High Speed Maglev Transport Electromagnetic and Electrodynamic Levitation Transrapid System (Germany) Yamanashi Maglev Test Line in Japan Swissmetro Marine Express Building and Factory Transportation Systems Elevator Hoisting Machines Ropeless Elevators Assessment of Hoist Performance Horizontal Transportation systems Industrial Automation Systems Automation of Manufacturing Processes Casting Processes Machining Processes Welding and Thermal Cutting Surface Treatment and Finishing Material Handling Testing Industrial Laser Applications Appendix A Magnetic Circuits with Permanent Magnets Appendix B Permeances for Magnetic Fluxes Appendix C Performance Calculations for PM LSMs Symbols and Abbreviations References

Linear Synchronous Motors : Transportation and Automation Systems

This paper develops and analyzes a parametric model for simulating healthy and faulty surface-mounted permanent magnet synchronous motors. It allows studying the effects of stator winding interturn short-circuit faults. A relevant feature of the developed model is that it deals with spatial harmonics due to a nonsinusoidal rotor permanent magnet configuration. Additionally, the proposed model is valid for studying the behavior of these machines running under nonstationary conditions, including load or speed variations. Stator current spectra obtained from simulations performed by applying the proposed model show a close similitude with experimental results, highlighting the potential of such a model to understand the effects of stator winding failures on the current spectrum and allowing it to carry out an automatic diagnosis of such faults.

Modeling of Surface-Mounted Permanent Magnet Synchronous Motors With Stator Winding Interturn Faults

This paper presents the study on the analysis method of axial force for general rotating machine having radial air-gap flux by axisymmetric 2-D finite element method (FEM). Axial force due to the gap in axial direction between stator and rotor causes damage to bearings, shaft and coupler. In order to use 2-D FEM, we propose some assumptions and a modeling method. The experiment by using measuring instrument on the shaft end is performed for the verification of analysis method. The minimizing axial force is also suggested by adjusting radial duct in the machine

Analysis of Axial Magnetic Force Distribution Due to the Axial Clearance for Electrical Rotating Machine

- In this paper, effective design method of linear induction motor(LIM) for Maglev is proposed in order to maximize system efficiency of Maglev. For the high system efficiency of Maglev, it is important to minimize weight of traction motor. Light weight design by changing materials of core and winding is conducted without changing volume of LIM. For the silicon steel core of primary part for magnetic flux path, iron-cobalt alloy steel with high magnetic saturation characteristic compared to silicon steel is suggested. Moreover, aluminium winding with light weight instead of copper winding is wounded in the widen slot area due to the high magnetic saturation level. For the verification of performance of proposed model, the characteristics are analyzed by using finite element method(FEM). Key Words : Maglev, Linear induction motor, Light weight, Cobalt steel, High efficiency†Corresponding Author : Department of Electrical Engineering, Hanbat National University, Korea E-mail : kckim@hanbat.ac.kr* Dept. of Electrical Engineering, Kiee Univerity, Korea Received : November 24, 2015; Accepted : March 17, 2016

A Study on Design of Linear Motor for Maglev for High Efficiency

This paper presents a new approach to reduce windage loss of SRM by changing the rotor shape. To predict the performance of improved SRM rotor, the dynamic characteristics analysis is needed using inductance profile. The calculation values are compared with the measurement ones, in order to evaluate a validity of the proposed method

Performance Prediction of Switched Reluctance Motor Considering Windage Loss for High Speed Application

Bracket structure of traction motor for electric railway stocks

In order to reduce the torque ripple of the synchronous reluctance motor (SynRM), the skew of the rotor is used to be chosen. The 2D finite element method (FEM) or 3D FEM is used to analyze the skewing motor. However, the 2D or 3D FEM analyses generally take much time. This paper analyzes the characteristic of skewed SynRM using equivalent magnetic circuit considering flux density harmonics contents

Ki-Chan Kim

Papers

Analysis of Axial Magnetic Force Distribution Due to the Axial Clearance for Electrical Rotating Machine

A Study on Design of Linear Motor for Maglev for High Efficiency

Performance Prediction of Switched Reluctance Motor Considering Windage Loss for High Speed Application

Bracket structure of traction motor for electric railway stocks

Analysis of Synchronous Reluctance Motor using Equivalent Magnet Circuit considering Skew and Flux Density Harmonics Contents