• 조명전기설비학회논문지
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• 제28권9호
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• pp.67-72
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• 2014

Inflow or outflow from the water treatment plant and the sewage water has potential energy. If this potential energy can be converted into electrical energy by water turbine generator, it can help to save energy because of the high capacity utilization. So recently, micro hydro power plant is reviewed in the water treatment facility. If generation capacity is low, induction generator is primarily used. If output capacity is low, generated power is supplied to the inside load. Induction generator can cause voltage drop by the inrush current at a start-up and requires reactive power for magnetization. In this study, we analyzed the flow of power and voltage variation against inrush current that occurs when the induction generator starts under the terms that loads of linear and non-linear of the water purification plant are used. Analysis results are that the voltage drop is within an allowable range and the power factor is slightly reduced by the need of reactive power.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.198-200
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• 2007

A linear generator driven by hydrogen (or other kind of fuel) combustion engine requires special consideration for starting because of its none-conventional way of operation. This study investigates the possibility of replacing mechanical (hydraulic) start-up with electrical motoring. Simulation study based on 1 kW prototype system shows that the mover position of a linear generator can be controlled with a proper current control of power converter.

• Journal of Electrical Engineering and Technology
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• 제12권3호
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• pp.1219-1226
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• 2017

This paper presents the hybrid stepping machine for linear oscillating generators. The focus of the work is the suggestion of the improved model through the comparison of proposed models ; new flux concentrating PMs mover of the hybrid stepping generator is proposed based on the symmetrical and non-symmetrical stator cores of the surface mounted PMs mover, and non-slanted PMs and slanted PMs of the flux concentrating PMs mover. It is achieved using equivalent magnetic circuit considering leakage elements. Finally, this study suggests new hybrid stepping structure of linear oscillating generator.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.29-32
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• 2006

Recently, many researches of the alternative and renewable energy have introduced due to the increasing oil price, the limited natural resources and the environmental pollution. In case of hydrogen energy, it has some merits, which can be substituted the existing the fossil fuel because of no contaminants from the combustion and the chemical reaction. We have been developing 1kW Hydrogen Linear Generator. In this paper, the thermal characteristic of this prototype linear generator has been investigated and obtained reliable analysis results comparing with experimental measurements. Especially, it is predicted that in case of 1kW, 60Hz test sample, the results satisfy with the temperature standards of H type insulation, which is shown average $69.0^{\circ}C$ temperature distribution at the coil.

• 한국수소및신에너지학회논문집
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• 제26권6호
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• pp.638-644
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• 2015

This paper describes the continuing effort to analysis and design on dynamic and electrical behavior of gamma-type free piston Stirling engine/generator with dual-opposed linear generator for domestic micro-CHP (Combined Heat and Power) system. The double acting Stirling engine/generator has one displacer and two power piston which are supported by flexure springs. Two power pistons oscillate with symmetric sinusoidal displacement and are connected with moving magnet type linear generators for power generation. To operate Stirling engine/generator, combustion heat of natural gas is supplied to hot-end and heat is rejected from cold-end by cooling water. The temperature difference across the displacer induces the oscillating motion, and it can be explained with mass-spring vibration system. The purpose of this paper is to describe the design process of linear generator for the double acting free-piston Stirling engine.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2005년도 학술대회 논문집
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• pp.95-99
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• 2005

This paper presents a general proposal to design and calculate the performance of a tubular permanent magnet linear generator treated here on the basis of the Finite Element Method. Optimizing the linear generator dimensions reduces the cogging force, which occurs due to the interaction between stator teeth and the permanent magnets. The generated AC voltage is analyzed and evaluated for both no load and load cases to take the armature reaction effects on the air gap flux density. A repetitive routine is followed to calculate the output AC voltage from the change of flux and the speed of the single-phase linear generator. The AC output voltage is calculated for different resistive loads, and hence, the linear generator load characteristic is obtained. The designed linear generator is capable to generate an output power of 5.3kW with AC output voltage of 222V with an efficiency of 96.8% at full load of 23.8A. The full load current is chosen based on the thermal properties of the coil wire insulations.

• Journal of Power Electronics
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• 제6권4호
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• pp.290-297
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• 2006

Various methods have been discussed to reduce detent force in a tubular permanent magnet type linear single phase AC generator. In particular, the proposed methods depend on variations of the permanent magnet construction. These methods include two approaches in the form of sloped magnets, and conical magnets in addition to the conventional method of optimizing the magnet length. The undesired detent force ripples were calculated by a two dimensional Finite Element Method (FEM). Moreover, the generated electromotive force in the stator coils was calculated for each configuration of the permanent magnet. The experimental results agreed well with those obtained from the FEM-based simulations. Sufficient reduction in the detent force was achieved over the range of 40% while the root mean square of the output voltage was maintained. It was found that sloping the permanent magnet decreased the detent force and at the same time increased the generated rms voltage of the AC generator. The performance of the designed linear AC generator was evaluated in terms of its efficiency, total weight, losses, and power to weight ratio.

• 정보보호학회논문지
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• 제12권3호
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• pp.77-85
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• 2002

선형 쉬프트 레지스터를 이용한 이진 난수 발생기의 연구는 1970년대부터 연구되어져 왔으며, 이러한 이진 난수열 발생기는 스트림 암호 기법에 이용되어졌다. 일반적으로, 이진 난수열 발생기는 최대 주기의 선형 쉬프트 레지스터와 선형 복잡도가 높은 난수를 발생시키기 위하여 비선형 여과함수 또는 비선형 결합함수로 구성된다. 그러므로, 높은 선형 복잡도 뿐만 아니라, 긴 주기를 갖는 이진 난수열의 생성은 스트림 암호 기법의 안전성을 평가하는데 중요한 요소가 된다. 일반적으로 L개의 레지스터와 1개의 궤환 함수 또는 특성 다항식으로 구성된 선형 쉬프트 레지스터의 최대 주기는 $2^L$-1을 넘을 수 없다. 본 논문에서는 L개의 레지스터와 2개의 부분 특성 다항식으로 구성된 새로운 이진 난수열 발생기를 제안한다. 제안된 이진 난수열 발생기는 초기 상태 값에 따라 기존의 선형 쉬프트 레지스터에서 생성한 수열의 주기와 같거나 긴 주기를 갖는 이진 난수열을 생성하며, 생성 수열의 선형복잡도 역시 증가된다.

• 전력전자학회논문지
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• 제13권3호
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• pp.163-170
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• 2008

본 논문에서는 DVR 등의 전력품질 개선장치들의 성능시험에 용이하게 사용하기 위하여 제안한 3상 전압변동 발생기에 대하여 선형뿐만 아니라 비선형 부하에서도 동작이 가능함을 보이는 스위칭 특성해석을 하였다. 선형 부하의 경우는 전류가 연속이므로 전압변동 발생기를 구성하는 SCR 사이리스터의 자연전류(natural commutation)가 용이하게 발생하지만, 비선형 부하의 경우는 전류 불연속 모드 동작이 발생하여 SCR 사이리스터의 원활한 스위칭이 이루어질 수 없는 경우도 있다. 따라서 비선형 부하 시 전류 불연속 구간에서의 SCR 사이리스터의 스위칭 패턴을 분석하여 전압 새그(sag), 스웰(swell), 순간정전(outage), 전압불평형(voltage unbalance) 동작이 선형에서와 동일하게 발생되는 조건을 파악하였다. 각각의 기능을 발생시키는 원리와 동작 특성을 해석하였으며 시뮬레이션과 실험을 통하여 성능을 확인하였다. 본 논문에서 다룬 전압변동 발생기는 전원 외란 발생을 낮은 비용으로 구현해 낼 수 있고 구조와 제어가 간단하여 전력품질 개선과 관련된 연구를 하는데 용이하게 활용될 것으로 기대한다.

• Nuclear Engineering and Technology
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• 제33권1호
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• pp.102-110
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• 2001

In this work, the model predictive control method was applied to a linear model and a nonlinear model of steam generators. The parameters of a linear model for steam generators are very different according to the power levels. The model predictive controller was designed for the linear steam generator model at a fixed power level. The proposed controller at the fixed power level showed good performance for any other power levels by designed changing only the input-weighting factor. As the input-weighting factor usually increases, its relative stability does so. The steam generator has some nonlinear characteristics. Therefore, the proposed algorithm has been implemented for a nonlinear model of the nuclear steam generator to verify its real performance and also, showed good performance.