Ki-Bong Jang

Optimal Design of Auxiliary Teeth to Minimize Unbalanced Phase Due to End Effect of PMLSM

Discontinuity of magnetic circuit according to the end effect is generated in the PMLSM. Due to the unbalanced magnetic state, the unbalanced inductance and unbalanced back-EMF is produced. In this paper, the effects of circulating current due to the end effect are analyzed by FEA (Finite Element Analysis). By using FEA and DOE (Design of Experiment), an optimal design of the auxiliary-teeth model is carried out to decrease circulating current. And the effect of the unbalanced phase based on the auxiliary-teeth installation is considered.

The Improved Design of Double Sided Coreless PMLSM with Consideration of Rising Winding Temperature

This work deals with the optimal design of a coreless PMLSM (Permanent Magnet Linear Synchronous Motor) with consideration of rising winding temperature. The temperature distribution caused by copper loss in the coreless PMLSM was analyzed using a FEM (Finite Element Method). The thrust and current density where the winding temperature reaches the allowable temperature were calculated. The optimal model provides maximum thrust per unit weight.

Design of permanent magnet assisted synchronous reluctance motor with external rotor architecture

This paper proposes an external rotor Permanent Magnet assisted Synchronous Reluctance Motor (PMa-SynRM). Due to the high material cost of PM machine, there was a continuous effort to reduce the amount of permanent magnets (PM) in manufacturing an electric machine. PMa-SynRM has reduced great amount of PM usage by hybridizing the architectures between Synchronous Reluctance Motor and Permanent Magnet Motor. To further reduce the PM usage and to further increase of torque density, design of PMa-SynRM has been investigated through external rotor architecture. With best of authors knowledge, external rotor has not been properly researched even with great advantage and design flexibility with PMa-SynRM architecture. Analytical comparison between two different types of motor (internal and external) has been investigated to prove the superior design flexibility and performance of proposed method. Performance characteristics such as average torque developed and variation of torque with respect to variation in speed have been analyzed in finite element atmosphere (FEA) to validate the proposed design. A lower torque ripple model with distributed winding structure has been modeled and its FEA simulation results for developed torque have been compared with the concentrated type external rotor PMa-SynRM model.

Optimization of rotor shape for constant torque improvement and radial magnetic force minimization

The design of notch and barrier was optimized in order to improve the characteristics of constant torque while minimizing the cogging torque that occurs as a result of teeth and slot structure. The barrier was installed in order to minimize the cogging torque and torque ripple by finite element method (FEM) with a reduced barrier width toward the center of magnetic pole. The position and width of notch, which can offset cogging torque, can be calculated with energy distribution of air-gap using Fourier series. The optimized model demonstrates a 60% decrease in the cogging torque, a 75.3% decrease in the torque ripple and a 3% increase in the operating torque when compared with the basic model.

A Study on the Characteristics of PMLSM According to Permanent Magnet Arrangement

This paper deals with the characteristics of permanent magnet linear synchronous motor according to the permanent magnet arrangement. The thrust, detent force, normal force and lateral force are generated in the permanent magnet linear synchronous motor. The detent force and lateral force cause the vibration of permanent magnet linear synchronous motor. The 3-D FEM is used to consider the effect of the skew and the overhang effect. Simulation values are compared with experimental ones. Furthermore characteristics of vibration and efficiency are estimated by experiments.

The Inductance Computation of IPMSM using Direct-current Diminution Test

This paper deals with a reduction of cogging torque and estimate of inductance for IPMSM. The flux barriers(Barrier) and the auxiliary slot(Notch) for the reduction of cogging torque was installed for increase of driving characteristic in IPMSM. The cogging torque, driving torque and inductance are analyzed by using FEM(Finite Element Method) and the results of inductance calculation are compared to experimentation ones.

Thermal Analysis of IPMSM According to Current Vector Control Method

Nowadays, Interior permanent magnet synchronous motor(IPMSM) which having high power density is much used for the vehicles. However, IPMSM causes a lot of losses because of high-speed driving and high current density, and temperature rising by iron loss and copper loss could reduce torque characteristics and durability of IPMSM. Therefore, analysis about thermal characteristics of IPMSM is required at design stage. In this paper, temperature characteristics according to current vector control method were analyzed through calculate thermal equivalent circuit. And calculated results were verified through comparing with the experiments.

The Optimization of Rotor Shape for Constant Torque Improvement and Radial Magnetic Force Minimization

In this paper, the optimal design of notch and barrier was carried out in order to improve characteristics of constant torque with minimizing the cogging torque occurred by teeth and slot structure. Optimized design was carried out by design of experiment and various characteristics including torque were studied by finite element method(FEM). In addition, in order to verify resonance frequency, natural frequency of the stator was analyzed by modal analysis.

The estimation of torque ripple according to parameters considered with time varying in voltage equation

Torque calculation using the d-q axis has the advantage of faster execution time; however, the torque ripple cannot be considered in torque calculation using the d-q axis equivalent circuit because the time-dependent component is removed. In this work, with d-q transformation, the characteristics of some parameters were identified. These characteristics were considered for representing torque ripple. Calculation with d-q axis transformation and finite-element analysis (FEA) was performed, and the results obtained using these two approaches were compared. It was verified that the calculated torque can be expressed with ripple.

Analysis of IPMSM temperature characteristics based on stator parameters

In this paper, the effect of changes in the width of teeth and yoke on stator temperature characteristics was analyzed. An initial model of fill factor 45% was produced. The validity of the temperature analysis using the thermal equivalent circuit method was experimentally verified. A basic model was selected as the initial model. Also, a temperature characteristic analysis was performed for various widths of stator teeth and yoke, and the effects were analyzed.