Analysis and Experiments of the Linear Electrical Generator in Wave Energy Farm utilizing Resonance Power Buoy System

Sang-Shin Park,Se Myung Park,Jongkyo Jung,Jin Ho Kim 한국자기학회 2013 Journal of Magnetics Vol.18 No.3

In this research, the linear electrical generator in wave energy farm utilizing resonance power buoy system is studied. The mechanical resonance characteristics of the buoy and the wave are analyzed to maximize the kinetic energy in a relatively small wave energy area where WRPS is operated. In this research, we chose an analog model of the linear electrical generator of which size is one-hundredth of an actual size of it in WPRS (Wave energy farm utilizing Resonance Power buoy System) prior to verifying the characteristics of actual model of linear electrical generator in WRPS. In addition, the finite element analysis is conducted using commercial electromagnetic analysis software named MAXWELL to examine the electric characteristic of linear generator. Finally, for the verification of dynamic and electric characteristics of linear generator, the prototype was manufactured and the experiments to measure the displacement and the output electric power were performed.

Free-Piston 엔진용 평판형 선형 발전기를 이용한 기동모드 해석

金榮旭(Young-Wook Kim),林栽元(Jaewon Lim),鄭炫敎(Hyun-Kyo Jung) 대한전기학회 2008 전기학회논문지 Vol.57 No.6

Free-piston engine system is a new type energy converter which uses a linear motion of piston by using linear generator. in free-piston engine system, the piston is not connected to a crank-shaft. The major advantages of free-piston engine system are high efficiency and low mechanical loss from the absence of motion conversion devices. Linear generator of free-piston engine system is used as generator and starting motor. in design step, considering of back-emf and detent force characteristics for generating mode and thrust and control characteristics for starting mode is needed. In this research, generating mode of flat-type Linear generator and tubular-type linear generator is analyzed by finite element analysis method and starting mode of both type linear generators is analyzed by using capability curve. Capability curve is plotted from electrical parameters of both type linear generator and motion profile is calculated from mechanical parameters.

세라믹 리니어엔진을 이용한 소형 전기자동차용 온보드 제너레이터 개발

김남열(Nam Yuer Kim),표영덕(Young Dug Pyo),임옥택(Ock Taeck Lim),김강출(Gang Chul Kim) 한국자동차공학회 2009 한국자동차공학회 부문종합 학술대회 Vol.2009 No.4

In the realm of small electric vehicles (neighborhood electric vehicles or personal electric vehicles such as electric wheelchairs, electric scooters etc.), there's a power struggle brewing. They demand lots of electrical power and long operation, but current rechargeable battery cannot provide the operational durations required. Also short lifetimes of batteries impose a fundamental limitation. Due to these reasons, a small linear reciprocating engine and linear electric generator are designed in this paper. If an engine is used solely to produce electrical power, it is not necessary to convert the reciprocating linear motion of the piston to rotary motion by crank. Instead, a linear electrical generator may be coupled directly to the piston for a conversion of mechanical energy into electrical energy. Such a design has many advantages such as mechanical simplicity and low friction and it can make possible a small engine having high efficiency. In other words, linear engines give power output more efficiently compared to conventional reciprocating piston engine, because it doesn't have a crank mechanism, hence there is less mechanical loss. In this study, we developed a small sized linear engine for the electrical power generation. To increase the efficiency and endurance, we made a piston and cylinder sleeve by ceramic materials.

Detent Force Reduction of a Tubular Linear Generator Using an Axial Stepped Permanent Magnet Structure

Ahmad M. Eid,Hyun Woo Lee,Mutsuo Nakaoka 전력전자학회 2006 JOURNAL OF POWER ELECTRONICS Vol.6 No.4

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.

양방향 스털링엔진의 선형발전기 설계에 관한 연구

박성제,고준석,홍용주,김효봉,염한길,인세환 한국수소및신에너지학회 2015 한국수소 및 신에너지학회논문집 Vol.26 No.6

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.

차량 노면 진동을 이용한 공진형 선형 발전기 시스템의 강건최적설계

최지현(Ji Hyun Choi),김진호(Jin Ho Kim),박상신(Sang-Shin Park),서태원(TaeWon Seo) 한국생산제조학회 2014 한국생산제조학회지 Vol.23 No.4

To use vibration energy to generate electricity, a resonance vertical linear electric generator was applied to the suspension of a vehicle in a previous paper. However, the working conditions, including mass change in the vehicle body related to the cargo on board, number of passengers and the temperature difference caused by the operating environment, can influence the permanent magnet, which is the main component of the electric generator. Therefore, a robust optimum design is required to minimize the influences from the diverse operation conditions and maximize the electromotive force of the electric generator. In this paper, a resonance linear electric generator is introduced. Vibration response analysis to find the input velocity of the electric generator and an electromagnetic transient analysis to apply changes in the performance of the permanent magnet are performed. Finally, the optimum value of each design variable is derived using a Taguchi method.

Static Var Generator Based on Accurate Linearization Combined with Sliding Mode Controller

Liu Fei,Wang Xueyan,Huang Xinyi,Yan Honglin,Huang Xiangdong,Pan Hongguang 대한전기학회 2022 Journal of Electrical Engineering & Technology Vol.17 No.5

The active and reactive current are hard to be decoupled completely with strong robustness when the traditional proportional integral (PI) algorithm is adopted to feedforward decoupling control for static var generator (SVG). This paper proposed a compound control strategy for SVG based on precise linearization and sliding mode control (SMC). To be specifi c, fi rst, the theory of diff erential geometry is used to prove that the mathematical model of SVG satisfi es the necessary and suffi - cient condition of precise linearization. Second, the precise linearized high-order system of SVG was transformed into two completely independent decoupled fi rst-order linear systems, and realize complete decoupling of active current and reactive current. Finally, SMC was used to design both the voltage outer loop and the current inner loop. Simulations ware carried out for the SVG mathematical model under three conditions which were inductive load, capacitive load and sudden change load. The results of those simulation showed that the controller designed by the proposed control strategy has the advantages of quick reactive power compensation, strong robustness and anti-interference performance.

OPTIMIZATION OF OPERATION PARAMETERS OF 80-KEV ELECTRON GUN

Kim, Jeong Dong,Lee, Yongdeok,Kang, Heung Sik Korean Nuclear Society 2014 Nuclear Engineering and Technology Vol.46 No.3

A Slowing Down Time Spectrometer (SDTS) system is a highly efficient technique for isotopic nuclear material content analysis. SDTS technology has been used to analyze spent nuclear fuel and the pyro-processing of spent fuel. SDTS requires an external neutron source to induce the isotopic fissile fission. A high intensity neutron source is required to ensure a high for a good fissile fission. The electron linear accelerator system was selected to generate proper source neutrons efficiently. As a first step, the electron generator of an 80-keV electron gun was manufactured. In order to produce the high beam power from electron linear accelerator, a proper beam current is required form the electron generator. In this study, the beam current was measured by evaluating the performance of the electron generator. The beam current was determined by five parameters: high voltage at the electron gun, cathode voltage, pulse width, pulse amplitude, and bias voltage at the grid. From the experimental results under optimal conditions, the high voltage was determined to be 80 kV, the pulse width was 500 ns, and the cathode voltage was from 4.2 V to 4.6 V. The beam current was measured as 1.9 A at maximum. These results satisfy the beam current required for the operation of an electron linear accelerator.

Optimization of Operation Parameters of 80-keV Electron Gun

김정동,이용덕,강형식 한국원자력학회 2014 Nuclear Engineering and Technology Vol.46 No.3

A Slowing Down Time Spectrometer (SDTS) system is a highly efficient technique for isotopic nuclear material contentanalysis. SDTS technology has been used to analyze spent nuclear fuel and the pyro-processing of spent fuel. SDTS requiresan external neutron source to induce the isotopic fissile fission. A high intensity neutron source is required to ensure a high fora good fissile fission. The electron linear accelerator system was selected to generate proper source neutrons efficiently. As a first step, the electron generator of an 80-keV electron gun was manufactured. In order to produce the high beampower from electron linear accelerator, a proper beam current is required form the electron generator. In this study, the beamcurrent was measured by evaluating the performance of the electron generator. The beam current was determined by fiveparameters: high voltage at the electron gun, cathode voltage, pulse width, pulse amplitude, and bias voltage at the grid. Fromthe experimental results under optimal conditions, the high voltage was determined to be 80 kV, the pulse width was 500 ns,and the cathode voltage was from 4.2 V to 4.6 V. The beam current was measured as 1.9 A at maximum. These results satisfythe beam current required for the operation of an electron linear accelerator.

CARSIM- Simulink연동 해석을 이용한 전자기 현가장치의 상대변위 해석

김지혜(Ji-Hye Kim),김진호(Jin-Ho Kim) 한국산학기술학회 2018 한국산학기술학회논문지 Vol.19 No.5

본 논문에서는 차량 주행 시 노면으로부터 진동 에너지를 흡수해 에너지 하베스팅을 통해 전기에너지 발생이 가능한 전자기 현가장치의 구조와 현가장치 내에 결합되어 전자기 댐퍼 역할을 하는 8극 8상의 선형 발전기의 구조를 검토하였다. 실제 주행 노면에 따른 전자기 현가장치의 에너지 하베스팅 효과를 비교하기 위해 차량 시뮬레이션 프로그램인 Carsim과 Simulink를 연동하여 민군 겸용 차량 모델을 사용해 두 가지 실제 노면인 아스팔트 노면과 비포장도로 노면 조건에 대한 모의 주행시험을 수행한 결과, 아스팔트 노면과 비포장도로에서 현가장치의 상대 변위 각각 8mm, 13mm의 결과가 나타났다. 다음으로 전자기 현가장치 내에 결합된 선형 발전기를 모델링 하여 도출한 현가장치 상대 변위 값을 적용해 상용 전자기해석 프로그램인 ANSYS MAXWELL을 이용해 동일한 해석조건을 적용하여 해석 시간 0.3s 동안 전자기 시뮬레이션을 수행하여 시간에 따른 발전량 결과를 도출해 비교하였으며 비포장도로와 아스팔트 노면에서의 평균 발전량은 각각 198.6W, 98.7W로 비포장도로의 경우 103.7% 높은 값을 보이는 것을 확인하였다. 마지막으로 노면의 주파수와 현가장치 입력 변위가 발전 출력에 영향을 끼치는 민감도를 비교한 결과 두 변수의 민감도는 각각 1.725, 1.283으로 노면 주파수가 전자기 시뮬레이션 출력변수인 평균 발전량에 34.5 % 높은 영향을 끼치는 결과를 확인하였다. This study investigated the structure of an 8-pole 8-slot linear generator, which acts as an electromagnetic damper by combining the structure of an electromagnetic suspension device capable of generating electrical energy through energy harvesting by absorbing the vibration energy from the road surface while driving. To compare the energy harvesting effect of the electromagnetic suspension according to the actual road surface, a driving road test was simulated for two actual road conditions, an asphalt road surface and unpacked road surface condition, using a civilian combined vehicle model in conjunction with a vehicle simulation program, Carsim and Simulink. As a result, the relative displacements of the suspensions on the asphalt road surface and the unpaved road were 8 mm and 13 mm, respectively. By applying the suspension displacement value derived by modeling the linear generator coupled to the electromagnetic suspension, the simulation was then performed for an analysis time of 0.3s by applying the same analytical conditions using the commercial electromagnetic analysis program, ANSYS MAXWELL, The average power generation on the unpacked roads and asphalt roads was 198.6W and 98.7W respectively, which was 103.7% higher for unpackaged roads. Finally, to compare the sensitivity of the road surface frequency and the suspension input displacement to the power generation output, the sensitivity of the two variables was 1.725 and 1.283, respectively, and the road surface frequency had a 34.5% higher effect on the average power generation.