• Proceedings of the KIEE Conference
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• 2004.10a
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• pp.123-125
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• 2004

This paper presents the application of response surface methodology (RSM) to design optimization for two types of synchronous reluctance motors (SynRMs); one has 12 slots with distributed winding, and the other has 6 slots with concentrated winding, to improve the ratio between torque ripple and average torque. The usefulness of RSM in optimization problem of SynRM is verified as compared with the results of finite element analysis. In the end, the optimized two SynRMs are compared with SynRM currently used in air-conditioning compressor in connection with torque performance and loss.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.19 no.7
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• pp.736-745
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• 2009

Fuel cells convert a fuel together with oxygen in a highly efficient electrochemical reaction to electricity and water. Since the electrochemical reaction in the fuel cell stack dose not generate any noise, Fuel cell systems are expected to operated much quieter than combustion engines. However, the tonal noise and the broad band noise caused by a centrifugal compressor and an electric motor cause which is required to feed the ambient air to the cathode of the fuel cell stack with high pressure. In this study, the multi-camber perforated muffler is used to reduce noise. We propose optimized muffler model using an axiomatic design method that optimizes the parameters of perforated muffler while keeping the volume of muffler minimized.

• Proceedings of the SAREK Conference
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• 2004.11a
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• pp.99-99
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• 2004

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1213-1216
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• 1996

This paper describes a precise temperature control method for refrigerating and air conditioning systems. The control technique is based on the optimal servo control design method and the control algorithm is implemented on a personal computer. To control the precise temperature, two actuators such as an inverter for the compressor speed control and a stepping motor for regulating the expansion valve are used. The superheat and evaporator temperatures are chosen as the system output. So a multivariable system which has two inputs and two outputs to be controlled. The complicative model is identified by using an ARX(Auto Regressive eXogenous) model and the controller is designed by using the Matlab software.

• 연구논문집
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• s.29
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• pp.17-27
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• 1999

The experimental results of the 17K inertance tube pulse tube cryocooler for cooling cryosensors are presented in this paper. In prototype experiments, linear compressor is driven by linear motor, and inertance tubes are inserted between one liter reservoir and pulse tube. Design of the inertance tube pulse tube cryo-cooler is conducted by ARCOPTR program of NASA Ames Research Center. To find optimal conditions of inertance tube pulse tube cryocooler, no load temperature and refrigeration capacity according to the variations of inertance tube volume, reservoir volume and charging pressure are measured. and the cool down and load characteristics at the particular conditions are presented. As the representative results, no load temperature of the cold end is 52.7K and refrigeration capacity is 5W at 72K..

• Journal of Mechanical Science and Technology
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• v.17 no.1
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• pp.122-128
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• 2003

This paper presents a thermodynamic analysis of heat pump system using water as a heat source and heat sink. The primary object in this study is the optimization of exergetic efficiency. Two different systems, 2-stream and 1-stream system, are analyzed in detail. Mass flow ratio (the ratio of mass flow rate of water through evaporator to that through condenser) is identified as the most important parameter to be optimized. It is shown that there exists an optimum mass flow ratio to maximize exergetic efficiency. The variation of optimum exergetic efficiency of 2-stream system is quite small and the value lies between 0.2∼0.23 for the range of investigation in this study. However, far better performance can be obtained from 1-stream system. This means considerable irreversibilities are generated through condenser of the 2-stream system. The effects of adiabatic efficiency of compressor-motor unit on the overall system performance are also examined in the analysis.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.197-200
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• 2007

FCEV uses electric energy generated from fuel cell stack, thus all consisting parts must be re-designed to be suitable for electricity based system. Cathode air blower which supplies compressed air into fuel cell stack has similar shape of turbocharger, but a radial turbine of traditional turbocharger is removed and high speed BLDC motor is installed . Generally, maximum 10% of electric power of fuel cell stack is consumed in air blower, therefore an effective design of air blower can improve the performance of FCEV directly. This study will present an aerodynamic design process of an air blower and compare computational results with experimental data.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.970-971
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• 2008

본 논문은 하이브리드 전기자동차를 위한 에어컨 압축기용 구동 드라이브에 대해 연구하였다. 전기자동차의 경우 열악한 환경에서 구동되기 때문에 센서리스 타입은 필수적이며, 고효율화와 고집적화를 위해서 매입형 영구자석 전동기 IPMSM (Interior Permanent Magnet Synchronizing Motor)을 사용하였다. 본 논문에서 사용된 IPMSM은 비정현적인 역기전력과 입력전류를 가지기 때문에 기존 IPMSM의 센서리스 방식은 불가능하다. 이를 해결하기 위해 최소차원의 관측기를 구성하고 속도함수에 의한 가변차단주파수에 의한 강인한 필터회로를 이용한 새로운 제어 알고리즘을 제안하였다.

• Proceedings of the KIPE Conference
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• 2006.06a
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• pp.10-12
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• 2006

BLDC 전동기와 같은 영구자석 전동기는 토크 각에 따라 출력 토크의 변화가 크기 때문에 원활한 기동 특성을 얻기 위해서는 회전자의 초기 위치 정보가 필수적으로 요구된다. 본 논문에서는 냉장고용 왕복동 압축기의 구동을 위해 사용되는 BLDC 전동기의 센서리스 구동장치에서 원활한 기동 특성을 얻기 위한 새로운 기동 제어 방식을 제안한다. 제안된 방식은 전동기의 전류 응답 특성으로부터 파악된 회전자 위치 정보를 이용하여 BLDC 전동기를 기동하는 방식으로, 압축기의 기동 부하 변동에 강인한 기동 특성을 가진다. 실험을 통하여 제안된 방식의 효과를 입증하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.08a
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• pp.55-58
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• 2003

IPMSM (Interior Permanent Magnet Synchronous Motor) is widely used in many applications such as an electric vehicle, compressor drives of air conditioner and machine tool spindle drives. In order to maximize the efficiency in such applications, this paper is proposed the optimal control method of the armature current. The controllable electrical loss which consists of the copper loss and the iron loss can be minimized by the optimal control of the armature current. The minimization of loss is possible to realize efficiency optimization control for the proposed IPMSM The proposed control algorithm is applied to IPMSM drive system, the operating characteristics controlled by efficiency optimization control are examined in detail by simulation.