International Journal of Applied Electromagnetics and Mechanics - Volume 39, issue 1-4

Authors: Lee, Jin-hee | Lipo, Thomas Anthony | Kwon, Byung-il

Article Type: Research Article

Abstract: This paper proposes a novel concentrated flux interior permanent magnet (IPM) type brushless DC (BLDC) motor that replaces low-price ferrite magnets, which has similar characteristics as the conventional IPM type BLDC motor that uses expensive NdFeB magnets. To minimize the cogging torque which is a disadvantage of the proposed model, optimal designs of rotor and permanent magnet were performed. In optimal design process, the Kriging method based on the Latin hypercube sampling (LHS) and a genetic …algorithm (GA) are applied due to suitability to non-linear data. Furthermore, to improve the average torque of the proposed model, the current excitation range was changed according to inductance. Through the optimal design process and the proper current excitation range, we show that the optimal model using low-price ferrite magnets has similar performance as the conventional IPM type BLDC motor using NdFeB magnets. Show more

Keywords: Ferrite magnet, FEM, concentrated flux, BLDC, IPM

DOI: 10.3233/JAE-2012-1565

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 957-963, 2012

Authors: Wang, Dao-Han | Zhu, Yu-Wu | Lee, Sang-Geon | Cho, Yun-Hyun

Article Type: Research Article

Abstract: The inherent drawback of iron-core type permanent magnet linear synchronous motor (PMLSM) is detent force that is dependent on several major factors such as pole-arc to pole-pitch ratio of magnet, slot clearance, and skewing. To minimize the detent force, this paper proposes a structure optimization using the combined computation of two dimensional (2-D) finite element method (FEM) and response surface methodology (RSM). The RSM, that is a collection of the statistical and mathematical techniques, is utilized …to predict the global optimal solution based on the FEM calculated results of the detect forces for different combinations of factors. With the help of the combined computation the high capacity iron-core type PMLSM with more than 12000 N propulsion forces only contains less than 3 N detent forces. Show more

Keywords: Permanent magnet linear synchronous motor, detent force, response surface method, optimization

DOI: 10.3233/JAE-2012-1566

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 965-971, 2012

Authors: Park, Seong-Cheol | Choi, Myoung-Hyun | Yuk, Kyeong-Jin | Kim, Byung-Taek

Article Type: Research Article

Abstract: In this paper, the effects of magnetization on the rotor conductor of a written-pole motor (WPM) are analyzed and then the shape of the conductor to maximize the amount of the magnetization is designed while the magnet on the rotor is magnetized by an exciter pole. The optimization is performed with design variables that are the shape and number of the rotor bars, where an objective function is set to the amount of magnetization satisfying a …constraint of the start-up time. The optimal design is verified by sequentially using a finite elements method and response surface method. Show more

Keywords: Self-start, synchronous motor, written-pole motor

DOI: 10.3233/JAE-2012-1567

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 973-980, 2012

Authors: Hong, Do-Kwan | Lee, Ji-Young | Woo, Byung-Chul | Chung, Shi-Uk | Kang, Do-Hyun

Article Type: Research Article

Abstract: This paper deals with the optimum design focused on an LHS (Latin hypercube sampling) experiment with the many design variables of a developed motor and comparison of the optimum algorithm. The effective design variables are selected by screening and analysis of means (ANOM). In this paper, the optimum design is achieved by using the comparison response surface methodology (RSM) with the genetic algorithm (GA) method as the multiobjective optimum design. The torque ripple ratio is satisfied …with a design goal within 3%. Therefore, multiobjective optimum design is considered between average torque and efficiency. The simulation results are compared with the experiment and show a deviation below 5%. Show more

Keywords: Outer rotor, spoke type direct-drive machine, turret application with large diameter, analysis of means (ANOM), Latin hypercube sampling (LHS), response surface methodology (RSM), genetic algorithm (GA) method

DOI: 10.3233/JAE-2012-1568

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 981-988, 2012

Authors: Zheng, Zhan-Feng | Zhu, Yu-Wu | Cho, Yun-Hyun | Dong, En-Yuan | Zou, Ji-Yan

Article Type: Research Article

Abstract: To make the ropeless elevator system (RLES) become practical, one of the most important requirements is the high force density. The slotted iron core type permanent magnet linear synchronous motor (PMLSM) seems to be the best choice except the large detent force. Therefore, in this paper the characteristics of detent force and propulsion force of PMLSM are investigated under different motor topology structures, such as different PMLSM topologies, different mover topologies, and different armature core topologies. …Finally, the long stator double-sided slotted iron-core type PMLSM with fractional slot winding is selected for the best performance. Show more

Keywords: Permanent magnet linear synchronous motor, actuator, detent force, response surface method

DOI: 10.3233/JAE-2012-1569

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 989-995, 2012

Authors: Terata, Mitusnobu | Fujii, Nobuo

Article Type: Research Article

Abstract: The characteristics of the high flux density linear synchronous motor (HFD-LSM) with the special field having V-letter array permanent magnets (PMs) are studied analytically by using a finite element method (FEM). For gap variation of plus or minus 4 mm to the typical gap 12 mm on the HFD-LSM with the thick PM of 40 mm, the change of thrust is only within 3% on the constant voltage drive. The change of efficiency is only within 0.5%. The …efficiency considered only the copper loss exceeds 0.95 even in the case of the double length supply. The power factor is about 0.88 for maximum thrust drive. The influence of PM thickness appears remarkably on the power factor. For 10 mm thick PM, the reduction rate of the power factor is about 45% compared with 40 mm thick PM. Show more

Keywords: Permanent magnet, synchronous motor, linear synchronous motor, high flux density, high thrust, high efficiency, high power factor, large reluctance, Transportation

DOI: 10.3233/JAE-2012-1570

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 997-1003, 2012

Authors: Ando, Yoshinori | Ugajin, Takatoshi | Baba, Akira | Fujita, Tomoyuki | Nagaya, Kousuke

Article Type: Research Article

Abstract: A non-contact gear mechanism is important for the non-contact transmission of a torque and a motion. In this paper, a magnetic gear system without contact which requires no lubricant oil is proposed. The driving gear consists of some iron discs with gear teeth whose shape is an involute curve. The discs of the follower gear are inserted in the gaps between the discs of the driving gear, and the attractive forces between the discs generate the …torque transmission. Using the magnetic gear system, a magnetically connected planetary gear device is developed. Moreover we measure and study the slip torque as static property, and the step-out torque as dynamic property due to implication of rotational speed. Show more

Keywords: Magnetic gear, layered discs, planetary gear, magnetic force, torque

DOI: 10.3233/JAE-2012-1571

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 1005-1011, 2012

Authors: Horiszny, Jacek

Article Type: Research Article

Abstract: The peak value of three-phase transformer's inrush current depends, among other factors, on value of the residual flux in the iron core. Higher residual flux produces the inrush current of greater value. Diminishing of magnetism in the core can reduce value of the current. This article presents demagnetization of the transformer as a method of inrush current reduction. In the method proposed a condenser is the source of energy for demagnetization. Different condenser capacitances and voltages …are implemented for calculation test to determine optimal values of these parameters. Later the residual flux established after demagnetization of the core is calculated for several initial values. Influence of the flux new value upon the inrush current is discussed. Show more

Keywords: Inrush current, residual magnetism, demagnetization

DOI: 10.3233/JAE-2012-1572

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 1013-1019, 2012

Authors: Nakamoto, Hiroyuki | Takenawa, Satoru | Kida, Yasuaki

Article Type: Research Article

Abstract: We propose a magnetic type tactile sensor that can measure a three-axis displacement and a three-axis force. The simple structure comprises two layers, an elastic layer and a substrate layer. The elastic layer is made of an elastic material and houses a cylindrical permanent magnet inside. The substrate layer is a glass epoxy board and has four giant magneto resistance (GMR) elements. The elements measure changes of magnetic field strength based on the displacement of the …magnet, and the three-axis displacement and force are calculated from the outputs of the elements. Features of this sensor are a wiring reduction, simple structure, and low cost. In this paper, we describe a structure of the sensor. We design a sensor which has two magnets inside, and confirm the performances of a prototype through the laboratory experiments. Show more

Keywords: Tactile sensor, electromagnetic, displacement, force measurement

DOI: 10.3233/JAE-2012-1573

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 1021-1026, 2012

Authors: Li, Jian | Lee, Sang-Geon | Cho, Yun-Hyun

Article Type: Research Article

Abstract: This paper presents the structure design and analysis of inner-rotor type axial-flux permanent magnet synchronous machines(AFPMs). The major sources of vibration in electric machines such as motors and generators are electric magnetic force distributed on both stators. The rotor suffers from unbalanced magnetic force when air gas are not symmetric on dual sides. In this paper, natural frequencies, mode shapes, and deformation were studied at normal and fault operations.

Keywords: AFPM, modal analysis, rotor deformation, unbalanced magnetic force

DOI: 10.3233/JAE-2012-1574

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 39, no. 1-4, pp. 1027-1033, 2012