Hyungwoo Lee

Dr. Hyungwoo Lee

orcid

Research Focus & Metrics

Academic Career Length

28Years (1999-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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9 March 2020 in Journal of Electrical Engineering & Technology
Verified
Journal Article
Closed access
PDF file
HAHanwoong Ahn
Hanwoong Ahn
HPHyun-Jong Park
Hyun-Jong Park
CKChanghyun Kim
Changhyun Kim
HLHyungwoo Lee
Hyungwoo Lee

12 July 2018 in IEEE Transactions on Magnetics
Verified
Journal Article
Closed access
WJWoo-Young Ji
Woo-Young Ji
GJGeochul Jeong
Geochul Jeong
CPChan-Bae Park
Chan-Bae Park
IJIk-Hyun Jo
Ik-Hyun Jo
HLHyungwoo Lee
Hyungwoo Lee
This paper proposes an all-in-one system for hyperloop that conducts propulsion, levitation, and guidance. Currently demand on high-speed long-distance transportation is increasing, so that hyperloop is getting attention and studied hard globally. Hyperloop is a new innovative transportation in which a levitated subsonic speed train travels through a vacuum cylindrical tube. Hyperloop needs functions of propulsion, levitation, and guidance for its service, and many devices are necessary for those functions. In the tube, a constrained space, many devices make the entire system complicated, and the size of the vehicle and tube are increased. Therefore, the costs of maintenance, manufacture, and construction are increased and control of each device becomes very difficult. But a non-symmetric double-sided linear induction motor (NSDLIM), the subject of this paper, is an all-in-one system that could conduct all functions. In this paper, the concept of NSDLIM was introduced and its possibility was suggested. Requirements of NSDLIM were investigated considering very high acceleration, velocity, and low air pressure. An NSDLIM model was designed and analyzed by using the finite-element method. Then, NSDLIM parameters that affect performance were investigated and adjusted to improve performance. The derived model performance was shown, and its possibility was considered.

24 May 2017 in IEEE Transactions on Magnetics
Verified
Journal Article
Closed access
SCSooyoung Cho
Sooyoung Cho
HLHuai-Cong Liu
Huai-Cong Liu
HAHanwoong Ahn
Hanwoong Ahn
JLJu Lee
Ju Lee
HLHyungwoo Lee
Hyungwoo Lee
This paper presents a new method for calculating the braking force of a drum-type eddy current brake with a two-layer structure. The drum-type eddy current brake should have a structure that improves the braking force by applying a material with high conductivity inside the drum because the eddy current loss generated from the drum is used as the braking force. In addition, because the eddy current brake operates at various speeds while braking the vehicle, it is necessary to grasp the braking force according to the speed. Furthermore, because the material of the drum is composed of non-laminated iron having conductivity, the skin effect and the armature reaction phenomenon appear, and the skin depth and the air-gap flux density are different depending on the braking speed. In this paper, the value of the eddy current loss of the eddy current brake with a copper coating inside the drum is newly presented and compared with the finite-element analysis results. In addition, the change in the speed-torque curve according to the conductivity value of the drum and inner coating material are shown. Finally, an experiment was conducted to compare and verify the characteristic curve of the eddy current brake obtained from the newly derived equations.

16 October 2018 in IEEE Transactions on Magnetics
Verified
Journal Article
Closed access
IJIk-Hyun Jo
Ik-Hyun Jo
HLHyungwoo Lee
Hyungwoo Lee
GJGeochul Jeong
Geochul Jeong
WJWoo-Young Ji
Woo-Young Ji
CPChan-Bae Park
Chan-Bae Park
This paper is a study on the application position of skew in order to reduce the cogging torque of a magnetic geared synchronous motor (MGM). The cogging torque affects the noise and vibration of the motor, so it should be reduced as much as possible. To solve this problem, a conventional permanent magnet (PM) synchronous motor is skewed to a PM. However, unlike other synchronous motors, the MGM has pole pieces (PPs), and a larger cogging torque is generated due to a larger reluctance difference. There have been few studies on the reduction of cogging torque of MGM, so it is essential to study the skew structure of MGM. Therefore, this paper has derived the optimum skew method by comparing and analyzing three models of MGM skewed to PM, PP, and PM and PP simultaneously.

27 May 2019 in IEEE Access
Verified
Journal Article
Open access
TKTaehyung Kim
Taehyung Kim
HLHyungwoo Lee
Hyungwoo Lee
SKSangshin Kwak
Sangshin Kwak
This paper presents switch fault detection and compensation control schemes for a modified dc-dc converter that relocates a diode location. The proposed fault detection and compensation control schemes are applicable to various energy generation systems that include energy storage. A fault detection index has been introduced to detect an open switch fault in the modified converter structure, and a compensation control method based on a mixed switching strategy has been developed. The fault-tolerant control method along with the detection scheme can make a system return to work even under a switch fault. The proposed schemes have been tested and verified both by simulations and by experiments using a TMS320F28335 DSP. The results will significantly improve the reliability of alternative energy generation systems against open switch faults.

22 September 2009 in IEEE Transactions on Magnetics
Verified
Journal Article
Closed access
SKSeung-Joo Kim
Seung-Joo Kim
HLHyungwoo Lee
Hyungwoo Lee
KKKwang S. Kim
Kwang S. Kim
JBJae-Nam Bae
Jae-Nam Bae
JIJong-Bin Im
Jong-Bin Im
JLJu Lee
Ju Lee
This paper presents a method to reduce torque ripple considering parameters with magnetic saturation. To estimate parameters of inductances for interior permanent magnet synchronous motor (IPMSM), the proposed method uses recursive least square (RLS) estimation algorithm. The estimated inductances are used for calculating torque and DC link voltage. Using the torque and the DC link voltage estimators, this control method can reduce torque ripple of IPMSM because of keeping linearity of inverter output. Therefore, the torque control system can achieve precise torque control. The proposed control method is verified by computer simulation and experiment.