• 산업기술연구
• /
• 제9권
• /
• pp.101-107
• /
• 1989

The magnetic forming system must be able to store very important electric energy, several tens kilojoules, and flow this energy through the forming coil within some hundreds microseconds. So several hundreds kiloamperes of current can flow through the branch conductor. For the good performance of this type of machine, internal impedance must be minimized. By the computation of distribution of current inside the conductors using integral equation method, we can obtain the inductance and resistance of some dispositions of branch conductors and by comparison obtain some principles for the design of branch conductors in the high power magnetic pulse generator.

• Journal of Positioning, Navigation, and Timing
• /
• 제1권1호
• /
• pp.29-34
• /
• 2012

A software GNSS signal generator for the GPS L1/L2/L5 and Galileo E1/E5 signals is proposed in this paper. And this signal generator is designed and implemented with several components by considering the reuse and expansion of components for similar GNSS signals. The characteristics of the reusability of the components are confirmed with the carrier generation and the band-pass filter components. And the functionality of the GNSS multi-band IF signal generator is validated by using the commercial software GPS L1 receiver, and the performance of signal acquisition, tracking and accuracy of horizontal position error are analyzed for this validation. As a result, the GPS L1 signal generator operates successfully and it could be expected that other signal generators also operate well because most of components are the same as those of the GPS L1 signal generator.

• 한국소음진동공학회논문집
• /
• 제23권3호
• /
• pp.267-273
• /
• 2013

Recently, turbine-generators have been replaced for the integrity reinforcement and the efficiency improvement, also, the blade's failures of LP turbines due to torsional vibration have been reported. Excessive torsional vibrations can result in failures of components. The severity of torsional oscillations and stress depends upon the separation margin between the excitation frequencies and torsional natural frequencies. Therefore it is needed to measure the torsional natural frequencies after replacement of the components to conform the separation margin of torsional natural frequencies. In this study torsional vibration measurements were performed after LP turbine and generator replacement and the torsional natural frequencies for the turbine-generator train were calculated to evaluate the effects of generator replacement on torsional natural frequencies of turbine-generator train. It is expected that these evaluation results will be used effectively to identify the root causes of torsional vibration problems.

• 한국기계가공학회지
• /
• 제15권4호
• /
• pp.141-147
• /
• 2016

A direct PM generator has the effect of reducing the mechanical noise and ease of maintenance by eliminating a number of power transmission components. In addition, wind turbines operating at low speed with the advantages of high output, high efficiency, and small size. The generator was designed as a small direct-drive PM generator that can be applied to a kite even at low wind speeds. The RPM (Revolutions Per Minute) of the reel was measured in two ways using a cadence/speedometer sensor and a tachometer while the actual kite. The RPM derived from the experiment was applied to the simulation on the designed generator. The no-load characteristic analysis for the magnetic fields produced for the permanent magnet generator by a permanent magnet and stator winding currents is achieved using a 2D coordinate system. A commercial electromagnetic analysis program, ANSYS Maxwell, was used to model the electromagnetic dynamics.

• 한국태양에너지학회 논문집
• /
• 제27권4호
• /
• pp.35-41
• /
• 2007

To demonstrate the desalination system, the demo-plant was scheduled to be installed. The system was planned to use solar thermal collector as heat source and PV as electricity source. For the design of the desalination demonstration system, firstly the solar thermal system would be well designed from the result between the supplied heat into the fresh water generator and the fresh water yield. The generator for demonstration system was chosen as the fresh water generator of the single stage and effect with plate-type heat exchanger using low pressure evaporation method. The test facility for the tests to reveal the relationship between the fresh water yield and the supplied heat flow rate was designed and manufactured. The maximum fresh water yield of two fresh water generators applied in this study was designed as 1.5 Ton/day. The parameters relating with the performance of fresh water generator are known as sea water inlet temperature, hot water inlet temperature, and hot water flow rate. Through the experiments, this study firstly showed detail operation characteristics of the generator and designed the solar thermal system for the demonstration system.

• 한국지진공학회논문집
• /
• 제7권2호
• /
• pp.85-92
• /
• 2003

본 논문에서는 교량의 건전도 감시용 자립형 계측유닛을 위한 교량의 상시진동을 이용한 진동발전시스템을 제시하였다. 본 연구에서는 전기자 반작용의 영향을 최소화한 새로운 구조의 진동발전기를 제안하고, 기계적 및 전기적인 설계식을 유도한 다음, 시험용 진동발전기를 제작하였다. 또한, 매우 작은 발전 전류의 축전시스템에 대하여 고찰하고 개선점을 도출하였다. 축전시스템에 대한 고찰 결과, 정류기에 사용된 다이오드 특성이 충전과정에서 지배적임을 밝혔다. 마지막으로, 진동발전시스템 모델에 실측 남해대교 가속도 데이터를 적용한 시뮬레이션과 실내 실험을 수행하였고, 제작된 시험용 진동발전기의 적용성과 효용성을 확인할 수 있었다.

• 대한방사선기술학회지:방사선기술과학
• /
• 제24권2호
• /
• pp.5-11
• /
• 2001

Most of X-ray generator had used rectifier type transformer with high tension generator which is supplied in a clinical diagnosis. Because the ripple rate of tube voltage is high, X-ray generating efficiency is very low. In these days, high tension generator for inverter type X-ray generator is being supplied from a broad which uses semi-conductor switching element for the electric power that have a high speed switching ability to solve these problem. But, semi-conductor element with large capacity is used with X-ray tube's large consumption power and diffusion is difficult in the small size hospital because production cost is going up by doing digital control through DSP. Therefore, this paper designed and manufactured CR type voltage divider for feedback control of tube voltage with high frequency resonance type inverter and for high tension transformer with high frequency. It was to make economical diffusion type X-ray generator which has wide output voltage and load extent. It was preyed that the X-ray generator had the stability of X-ray tube's output characteristics.

• Journal of Power Electronics
• /
• 제17권6호
• /
• pp.1422-1432
• /
• 2017

This paper presents a buck-boost converter-based bipolar pulse generator, which is able to generate bipolar exponential pulses across a resistive load. The concept of the proposed approach depends on operating the involved buck-boost converters in discontinuous current conduction mode with high-voltage gain and enhanced efficiency. A full design of the pulse generator and its passive components is presented to ensure generating the pulses with the desired specifications (rise time, pulse width, and pulse magnitude) for a given load resistance and input dc voltage. In case of moderate pulsed output voltages (i.e. few of kV), one module of the presented bipolar generator can be employed. While in case of high-voltage pulsed output, multi-module version can be employed, where each module is fed from an isolated dc source and their outputs are connected in series. Simulation models for the proposed approach are built to elucidate their performance in case of one-module as well as multi-module based generator. Finally, a scaled-down prototype for one-module of buck-boost converter-based bipolar pulse generator is implemented to validate the proposed concept.

• 항공우주기술
• /
• 제3권2호
• /
• pp.81-90
• /
• 2004

액체로켓엔진에서 터보펌프의 160kW급 터빈 구동용의, 액체산소와 케로신을 추진제로 사용하는 가스발생기의 탈설계점 연소성능시험 결과에 대해 논의하였다. 가스발생기의 탈설계점 연소시험에서 연소압력은 O/F비와 추진제 공급유량의 함수로 나타나는데, 출구 온도편차는 turbulence ring이 있는 경우 ±7.5K 이내로 매우 균일한 공간적 온도분포임을 확인하였다. 각각의 탈설계점 연소시험에서 가스발생기 출구 온도는 가스발생기로 공급되는 추진제의 O/F 비의 함수로 나타낼 수 있었다. 본 가스발생기의 탈설계점 연소시험 결과, 특히 가스발생기의 혼합비와 가스온도와의 관계는 향후 개발되어질 가스발생기 설계나 저혼합비 연소해석 코드를 작성 시 매우 유용하게 사용되어질 것이다.

• 대한기계학회논문집A
• /
• 제36권10호
• /
• pp.1147-1154
• /
• 2012

본 논문에서는 풍력발전기의 회전속도와 출력을 제어하기 위한 블레이드 피치 제어기 및 발전기 토크 제어 기법을 제시하고 비선형 시뮬레이션을 통하여 그 성능을 확인하였다. 회전속도 오차 및 출력오차를 이용한 양한정 함수를 정의하고 리아프노프 안정성 이론을 적용하여 정적 피치 제어기와 동적 토크 제어기를 설계하고, 제어기 설계 모델과 실제 적용 모델간의 차이를 보상할 수 있도록 시뮬레이션 기반 최적화를 이용하여 설계 인자 값을 결정하였다. 풍력발전기 제어기 설계에 가장 많이 사용되는 동력 전달계 모델을 기반으로 제어기 설계 절차를 예시하였고, 대표적으로 사용되는 비례-적분-미분 제어 및 최대 출력점 추종 토크 제어기와 성능 비교를 통하여 제안된 제어 설계 기법의 타당성을 검증하였다.