• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.338-339
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• 2011

본 논문에서는 SRC를 이용한 고효율 차량탑재형 충전기를 제안한다. 제안한 컨버터는 앞단의 부스트컨버터가 역률보상과 동시에 배터리의 전압 전류 제어를 수행하고 후단의 SRC를 고정듀티와 고정주파수로 동작시켜 전 부하영역에서 스위치와 다이오드의 ZCS 턴온 턴오프가 가능하다. 3.3kW의 시작품으로 부터 CC-CV 충전을 통한 제안한 방식의 타당성을 검증한다.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.147-148
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• 2011

In this paper, implementation of digital control for critical conduction mode power factor correction (PFC) rectifier is presented. Critical conduction mode is widely used in medium and low power conversion application due to its minimized MOSFET turn-on loss and diode reverse-recovery problem. However, it needs additional zero current detection circuit and maximum frequency limit to properly turn the MOSFET on and avoid the excessive switching loss in light load operation. This paper explains the digital IC implementation and verifies its operation with 200-W prototype PFC rectifier.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1992년도 하계학술대회 논문집 B
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• pp.1012-1015
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• 1992

A gate-turn-off thyristor (GTO) that has a fuction of self-commutation is a device that can be turned on like a thyristor with a single pulse of gate current and turned-off by injecting a negative gate current pulse. GTOs have been in existence almost from the beginning of thyristor era, recently are these devices being developed with large power-handling capabilities and improved performance, and they are gaining popularity In conversion equipment. In this paper, the effects of internal parameters of GTO model using a circuit containing two transistors and three resistors the switching operation and the turn-off snubber characteristics is investigated using SPICE program.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.863_864
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• 2009

Design and drive characteristics of SR drive for hydraulic pump system using passive converter is presented in this paper. In oder to get the high performance, a simple passive circuit is added in the front-end of a conventional asymmetric converter, which consists of three diodes and one capacitor. This passive converter has the high demagnetization voltage, to reduce the demagnetization time. Futhermore optimal turn-off angle for the proposed passive converter is proposed. According to motor speed and current, an optimal turn-off angle can be achieved by look-up table to reduce torque ripple. The characteristic of proposed hydraulic pump system using passive converter is verified by simulation and experimental results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.2019_2020
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• 2009

A recurrent surge oscillograph(RSO) test was performed at the Taean thermal power plant on #5 turbine generator. The test was conducted using a rotor reflectometer and digital oscilloscope. A DC voltage step is applied to each end of the rotor winding in turn. Each reflected wave, at the input end of the winding, is monitored and the two waveforms are superimposed automatically and monitored on a single channel oscilloscope. As the half windings in a rotor are identical, the two waveforms monitored at each end of the rotor will also be identical for a healthy winding. A winding with a fault will cause different voltages to be monitored at the two ends.

• Journal of Electrical Engineering and Technology
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• 제10권2호
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• pp.551-559
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• 2015

This paper's focus is in reducing the torque ripple and increasing the average torque by optimizing switching angles of 8/6 switched reluctance motor while implementing a robust speed controller in the outer loop. The mathematical model of the machine is developed and it is simulated using MATLAB/Simulink. An objective function and constraints are formulated and Optimum turn-on and turn-off angles are determined using Particle swarm optimization and Genetic Algorithm techniques. The novelty of this paper lies in implementing sliding mode speed controller with optimized angles. The results from both the optimization techniques are then compared with initial angles with one of them clearly being the better option. Speed response is compared with PID controller.

• Journal of Electrical Engineering and Technology
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• 제11권2호
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• pp.416-424
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• 2016

In this study, automatic detection of stator winding inter-turn short circuit fault (SWISCFs) in surface-mounted permanent magnet synchronous motors (SPMSMs) and automatic classification of fault severity via a pattern recognition system (PRS) are presented. In the case of a stator short circuit fault, performance losses become an important issue for SPMSMs. To detect stator winding short circuit faults automatically and to estimate the severity of the fault, an artificial neural network (ANN)-based PRS was used. It was found that the amplitude of the third harmonic of the current was the most distinctive characteristic for detecting the short circuit fault ratio of the SPMSM. To validate the proposed method, both simulation results and experimental results are presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.150-152
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• 2007

The stator faults yield asymmetrical operation of induction machines, such as irregular current, torque pulsation, increased losses and decreased average torque. So it is necessary to detect the stator faults and develope the monitoring system for detecting faults including vibration and noise. This paper describes the method to analysis the induction motors with the stator winding inter-turn short for investigation of the asymmetrical operation during normal and transient states. And a simple method is used for the simulation and analysis of the induction machines with stator asymmetries. Finally, simulation results, finite element analysis and experimental ones are presented. The results can be useful for real-time on-line monitoring of an induction motor.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.476-479
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• 2009

Unison의 U50 풍력발전기는 실증실험을 거쳐서 상용화 되어 시장에 제품으로 나와 있다. U50에 사용되는 영구자석 동기발전기는 Stator 내경 3.32 m 로 84극을 가지고 있으며 정격 25 rpm으로 운전되는 직접구동형이다. 직접구동형 발전기는 Gearbox 가 불필요한 반면에 높은 torque로 인해서 발전기가 무거운 단점이 있다. 기존의 U50 에 사용되는 발전기는 지지 구조물까지 포함할 경우 총중량이 약 20톤 이상이다. 발전기의 중량을 줄이고 경량화 시키기 위하여 slot에 들어가는 Ampere turn을 증가시키고 turn 수를 증가시켜서 기존과 유사한 전압, 전류, 출력을 유지하면서 축방향 Stator 길이를 감소시킨 최적화 모델에 대한 설계에 대하셔 연구를 진행하였으며 이 보고에서는 그 결과와 절차에 대해서 요약한다.

• 한국산업융합학회 논문집
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• 제5권3호
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• pp.179-186
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• 2002

This paper proposed LC resonant current fed high frequency inverter for high frequency induction heating using leakage inductance of transformer and, its described operating principle. The analysis of circuit presented by using normalized parameter in considering leakage inductance of transformer and, discussed characteristic evaluation of inverter circuit in detail. The proposed inverter is operating ZVS to reduce turn-on and turn-off loss of switching devices so, raised an efficiency. And, the experimental apparatus was made on base characteristic evaluation of theoretical analysis to discuss possibility on high frequency source and confirmed a rightfulness theoretical analysis. A result of study, the proposed inverter is higher utilizing factor using on leakage inductance of transformer and show possibility, which is application on high frequency power system.