• 전기학회논문지
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• 제56권2호
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• pp.301-310
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• 2007

Bidirectional DC-DC converters allow transfer of power between two dc sources, in either direction. Due to their ability to reverse the direction of flow of power, Dey are being increasingly used in many applications such as battery charge/dischargers, do uninterruptible power supplies, electrical vehicle motor drives, aerospace power systems, telecom power supplies, etc. This Paper Proposes a new bidirectional Sepic/Zeta converter. It has low switching loss and low conduction loss due to auxiliary communicated circuit and synchronous rectifier operation, respectively Because of positive and buck/boost-like DC voltage transfer function(M=D/1-D), the proposed converter is very desirable for use in distributed power system. The proposed converter also has both transformer-less version and transformer one.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.980-981
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• 2008

Mechanical spring and hydraulic pressure operated mechanisms are applied in most of today's High Voltage Gas Insulated Switchgear(GIS)s. This paper proposes a new type of operation mechanism for GIS circuit breakers rated at 245kV and 40kA. The Motor-Direct-Drive-Mechanism (MDDM) has many advantages compared to conventional operating mechanisms. It has a very simple structure with only one moving part, low mechanical stress and audible noise. It also allows monitoring, operation speed control and self-diagnosis functions.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1258-1259
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• 2008

In this paper, the variable tendency of the piezoelectric constant and resonance characteristics of the piezoelectric ceramics due to the electric field is studied. The practical application of piezoelectric ceramics is not only applied in field of small signal. For example, in case of an ultrasonic motor, 120 ${\sim}$ 130Vrms of driving voltage is needed. Therefore, to examine the characteristics of piezoelectric ceramics in large signal contributes to reducing the susceptibility to the multifarious application and securing the ease of the production of control circuit. These contributions may be connected to the expansion of industrial application. We fabricated disk-type piezoelectric ceramic samples by using conventional method and measured the resonance characteristics of these samples under from low to high voltage driving conditions. According to increasing the value of the input voltage, we measured the resonance frequency of the piezoelectric ceramic, and inquired into the cause of these phenomena.

• Journal of Electrical Engineering and Technology
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• 제8권1호
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• pp.118-123
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• 2013

This paper presents performance comparison between concentrated winding and distributed winding of IPMSM (Interior Permanent Magnet Synchronous Motors) which is recently used for light-weight railway applications. Motors are designed on various schemes and analyzed by using FEM (Finite Element Method) instead of EMCNM (Equivalent Magnetic Circuit Network Method) in order to take into account saturation and non-linear magnetic property. The overall performance such as torque, torque ripple, losses, demagnetization, efficiency, power density and so on are investigated in detail at the rated and maximum operating speed. The results of the analysis found that both concentrated and distributed winding IPMSMs are promising candidates for high power railway traction motor.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.79-80
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• 2015

This paper deal with the structure and the operating characteristics of the two-dimensional elevator system and the concept that supports to the circuit design for the driving control of the LIM in the simplest possible way. The Horizontal Axis, The Vertical Axis, that is to say, designed a motor that can move between two dimensions by using two of LIMs, especially this control system was described by a sequence control design drawing. The body of this paper has shown the characteristics and validity of this control design system and also analyzed how to apply operating characteristics of the LIM in the elevator industry.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.860-861
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• 2015

본 논문에서는 대용량 착자요크의 설계과정에서 최대입력 전류의 크기를 산정하기 위하여 해석적인 방법을 이용하여 산정하였다. 착자요크의 등가회로로부터 회로방정식을 도출하고 2차 미분방정식으로 표현하여 입력전류를 산정하였다. 산정된 입력전류는 회로해석 툴 및 유한요소해석을 이용한 상용소프트웨어와 비교하여 해석방법의 타당성을 검증하였다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.542-545
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• 2002

This paper deals with the optimization inverter design and minimization Conduced EMI noise by customizing IPM(Intelligent Power Module). Generally, In case of IPM, we realized that the trade-off relation between switching loss and spike voltage. Higher gate resistor causes tile lower spike voltage and the higher turn-off switching loss. But we know that the life cycle of inverter and the susceptibility of noise, so we optimized the gate resistor. Proposed method is that optimized the gate resistor suitable for the inverter and motor. The simulation and experimental results show that the spike voltage and Conduced EMI noise can be reduced without the additional circuit.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2002년도 전력전자학술대회 논문집
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• pp.158-162
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• 2002

This paper presents a novel 3-phase IGBT module called the SPM (Smart Power Module). This is a new design developed to provide a very compact, low cost, high performance and reliable motor drive system. Several distinct design concepts were used to achieve the highly integrated functionality in a new cost-effective small package. An overall description to the SPM is given and actual application issues such as electrical characteristics, circuit configurations, thermal performance and power ratings are discussed

• 전력전자학회:학술대회논문집
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• 전력전자학회 2003년도 추계학술대회 논문집
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• pp.275-278
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• 2003

Conventional vector control inverter is usually used for blower of air-accord equipment. In this paper, it is proposed that inverter is controlled by instantaneous following PWM controller. This controller compensate and follow for output voltage of inverter within one switching cycle as an error that compared output voltage of rectifier included much ripples with reference voltage of sine wave. It has not speedy response like vector controller, but the circuit is very simple as using analog integer. And it has advantages that develop input power factor, built small-capacity and low-cost because huge capacitor of voltage type inverter removed.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.352-356
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• 1998

This paper describes minimum current control method for size reduction and performances improvement at unified inverter-induction motor system. This control method is based on V/F without speed sensor. Through the use of minimum stator current points at required torque during V/F operation it is possible to minimize the size of heat-sink related with the losses of power circuit and to improve overall efficiency compared to conventional V/F control. Using this proposed scheme, it is so much more useful to apply to some fields such a selectric vehicles. air conditioning system and textile mills where the limited space is given and required low cost.