• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.303-305
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• 1996

A strategy that can maximize the efficiency of the inverter system for the non-magnetic material is proposed. Frequency control and variable DC-Link voltage control are compared and analyzed by the experimental results. The experimental results show the variable DC-Link voltage control is superior to the frequency control with respect to improve the efficiency of the inverter system. MOSFETs and IGBTs are used as switching devices and IGBTs are considerable as better switching devices for improving the efficiency of the inverter system.

• 전기학회논문지
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• 제63권11호
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• pp.1538-1544
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• 2014

In recent years, The electronic and energy industries demand low power consumption and high efficiency, so under their demands, the white goods industries which are represented for refrigerator and air conditioner system be implemented energy-saving power suppling structure with inverter control system. As inverter control system is different from step control type, when switching system is optimizing temperature control during short period, the inrush plus current can be flown in the circuit. In despite of these characteristics, there is no fuse which can be applied to this type until now. For this reason, we suggest the method of manufacturing protector in the high efficient inverter control system using the alumina-based ceramic radiated heat characteristics and metal films laminated plating. And through the evaluating electrical characteristics, we make a possible to utilize the method when designing overall fuses.

• 전력전자학회논문지
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• 제9권4호
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• pp.381-389
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• 2004

본 논문에서는 입력단 커패시터를 제거한 인버터의 제어에 아날로그 적분기를 이용한 새로운 비선형 제어 기법인 순시보상형 PWM 제어회로를 적용하고 있다. 비선형 순시보상형 PWM 제어기는 순시 입력전압의 변동에 대한 보상과 제어기준값에 대한 추종이 스위칭 한 주기 내에서 이루어지는 다이나믹하고 강인한 응답성을 가지고 있으며, 아날로그 소자를 사용하고 있어 제어회로가 간단하면, 인버터 입력 맥동전압을 보상함으로 대형의 평활용 커패시터가 필요치 않아서 소형, 저가형으로 부피가 적은 인버터를 제작 할 수 있다는 장점을 가지고 있다. 이러한 장점을 가지고 있는 순시보상형 PWM 제어 인버터를 기존의 VVVF 제어형 전동기 인버터 시스템을 대치하여 저가이고 소형의 인버터 시스템으로 제안하고 실험을 통하여 우수한 동작특성을 확인하고 있다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.2383-2388
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• 2011

LSMs are installed under girders along the long track. In order to improve the efficiency of the LSM, long stator LSM should be divided into the specified length and the propulsion inverters should have the system topology to generate high voltage and current for LSMs. This paper presents a system topology with two-step inverter in order to generate high voltage in inverter. A LSM propulsion system is developed and implemented in Maltab/Simulink. A system model of the two-step Inverter is applied to developed model. This paper demonstrates through simulation, advantages of multi-step inverter. The conclusions can serve the design of LSM propulsion system.

• Journal of Power Electronics
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• 제7권4호
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• pp.271-277
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• 2007

In this paper, an induction motor rotor fault diagnosis system using current signals, which are measured using the axis-transformation method is presented. Inverter-fed motor drives, unlike line-driven motor drives, have stator currents which are rich in harmonics and therefore fault diagnosis using stator current is not trivial. The current signals for rotor fault diagnosis need precise and high resolution information, which means the diagnosis system demands additional hardware such as a low pass filter, high resolution ADC, an encoder and additional hardware. Therefore, the proposed axis-transformation method is expected to contribute to a low cost fault diagnosis system in inverter-fed motor drives without the need for any additional hardware. In order to confirm the validity of the developed algorithms, various experiments for rotor faults are tested and the line current spectrum of each faulty situation, using the Park transformation, is compared with the results obtained from the FFT(Fast Fourier Transform).

• 전기학회논문지
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• 제60권5호
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• pp.971-976
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• 2011

This paper proposes a test system for a valve and poles building blocks used for large scale inverters such as STATCOM, SSSC, UPFC and VSC HVDC. Power semiconductors in the valve are normally connected in series to withstand switching voltage much larger than the voltage rating of a single power semiconductor. Therefore, there is a need to verify if the dynamic voltage sharing during switching in a valve is satisfactory. In this paper, we propose a test system that provides the necessary test condition: voltage and current in the valve using resonant circuits. A test scheme for a single phase inverter consisting two poles is also proposed. The performance of the inverter pole has to be verified at the factory test, before the system is installed at the site to secure the reliability of the system. The proposed scheme makes it possible to confirm if the pole can withstand voltage and current switching condition and handle loss.

• Journal of international Conference on Electrical Machines and Systems
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• 제1권2호
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• pp.91-97
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• 2012

This paper presents a state space model of a two quadrant chopper and PWM inverter-fed Interior Permanent Magnet Synchronous Motor (IPMSM) drive system and its application to hybrid vehicles. The drive system has two different state equations for motoring and regenerating action. This paper presents a common state equation by using State Space Averaging method. Using this model of the IPMSM drive system, detailed simulation and controller design of the drive system, including PWM inverter switching, are given. The validity of this model and usefulness, according to a comparison among Maximum Torque/Ampere control, Maximum Torque/Flux control, and Maximum Efficiency optimization, are confirmed from simulation results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1044-1045
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• 2008

DC transit system has been adopted in the metropolitan area, Korea since 1974. EMU in this system always reiterates that acceleration and retardation. When EMU decelerates using electric breaking, regenerative power occurs. Regenerative power can be consumed in vicinity EMU on the same line or in resistor. If DC transit system has inverter for reusing regenerative power, Energy efficiency in DC transit system will be increased. This paper present the adoption of developed inverter in commercial railway line and the test result procedure of developed inverter is presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.110-112
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• 2007

Output voltage waves of a DC/AC inverter system are likely to be distorted if variable loads e.g. motors or rectifiers exist in the output terminal. This paper designs a disturbance observer-based PI controller for a single-phase inverter system that is robust against load changes. In this paper, we regard the output voltage changes due to various loads as disturbances of the control system, Then we design a disturbance observer for estimation of the disturbances caused by the load current and any other error sources (such as parameter uncertainties and model mismatches etc.). In order to test the performance of the proposed control law, simulation studies are carried out for a single-phase inverter system using SimPowerSystems of Matlab Simulink. Compared to a simple PI control, the disturbance observer-based controller shows enhanced performance in transient responses for step load changes.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2003년도 추계종합학술대회
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• pp.333-336
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• 2003

태양광발전 및 소단위 풍력발전에 사용할 수 있는 변압기 없는 인버터를 설계하였다. 멀티 스위칭 방법에 의한 승압쵸퍼회로와 단상 풀브리지 인버터로 구성하였으며 소형화, 저 비용화를 위하여 변압기 없는 방식으로 설계하였다. 변압기 없는 시스템에서 문제가 될 수 있는 접지누설전류의 저감을 위해서는 스압쵸퍼의 스위칭기법 및 인버터 스위칭 등을 통하여 해결하였다.