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Ahmed, Tarek,Nagai, Schinichro,Soshin, Koji,Hiraki, Eiji,Nakaoka, Mutsuo The Korean Institute of Electrical Engineers 2003 KIEE International Transactions on Electrical Mach Vol.b3 No.1
This paper deals with the nodal admittance approach steady-state frequency domain analysis of the three-phase self-excited induction generator (SEIG) driven by the variable speed prime mover as the wind turbine. The steady-state performance analysis of this power conditioner designed for the renewable energy is based on the principle of equating the input mechanical power of the three-phase SEIG to the output mechanical power of the variable speed prime mover mentioned above. Us-ing the approximate frequency domain based equivalent circuit of the three-phase SEIG. The main features of the present algorithm of the steady-state performance analysis of the three-phase SEIG treated here are that the variable speed prime mover characteristics are included in the approximate equivalent circuit of the three-phase SEIG under the condition of the speed changes of the prime mover without complex computations processes. Furthermore, a feedback closed-loop voltage regulation of the three-phase SEIG as a power conditioner which is driven by variable speed prime movers such as the wind turbine(WT) employing the static VAR compensator(SVC) circuit composed of the thyristor phase controlled reactor(TCR) and the thyristor switched capacitor(TSC) controlled by the PI controller is designed and considered for wind-turbine driving power conditioner.
Ahmed, Tarek,Nagai, Schinichro,Soshin, Koji,Hiraki, Eiji,Nakaoka, Mutsuo The Korean Institute of Electrical Engineers 2003 KIEE International Transactions on Electrical Mach Vol.b3 No.1
This paper presents the digital computer performance evaluations of the three-phase self-excited induction generator (SEIG) driven by the variable speed prime mover such as the wind turbine using the nodal admittance approach steady-state frequency domain analysis with the experimental results. The three-phase SEIG setup is implemented for small-scale rural renewable energy utilizations. The experimental performance results give a good agreement with those ones obtained from the digital computer simulation. Furthermore, a feedback closed-loop voltage regulation of the three-phase SEIG as a power conditioner which is driven by a variable speed prime mover employing the static VAR compensator (SVC) circuit composed of the thyristor phase controlled reactor (TCR) and the thyristor switched capacitor(TSC) is designed and considered herein for the wind-turbine driven the power conditioner. To validate the effectiveness of the SVC-based voltage regulator of the terminal voltage of the three-phase SEIG, an inductive load parameter disturbances in stand-alone are applied and characterized in this paper. In the stand-alone power utilization system, the terminal voltage response and thyristor triggering angle response of the TCR are plotted graphically. The simulation and the experimental results prove the effectiveness and validity of the proposed SVC which is controlled by the Pl controller in terms of fast response and high performances of the three-phase SEIG driven directly by the rural renewable energy utilization like a variable-speed prime mover.
Yamamoto, Tetsuya,Yamamitsu, Fuminori,Sonoda, Toshikatsu The Korean Institute of Electrical Engineers 2012 The Journal of International Council on Electrical Vol.2 No.3
In recent years there has been increasing demand for the development of new "green" energy sources. Wind power generated using a self-excited induction generator has a drawback in that generated voltage varies with wind velocity. The authors first proposed the use of a single-phase magnetic flux controlled type variable reactor, and developed a system using three such reactors to achieve voltage control of an induction generator. The newly developed three-phase magnetic flux controlled type variable reactor was used to control the voltage of the induction generator. The authors have used an external power source (commercial power) for the voltage control source, and this approach would not be appropriate for use in remote locations. In the system described in this paper, however, a self-sufficient design was adopted that draws power required for voltage control from the generated power.
Design of digital nuclear power small reactor once-through steam generator control system
Qian Hong,Zou Mingyao 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.7
The once-through steam generator used in the small modular reactor needs to consider the stability of the outlet steam pressure and steam superheat of the secondary circuit to achieve better operating efficiency. For this reason, this paper designs a controllable operation scheme for the steam pressure and superheat of the small reactor once-through steam generator. On this basis, designs a variable universe fuzzy controller, first, design the fuzzy control rules to make the controller adjust the PI controller parameters according to the change of the error; secondly, use the domain adjustment factor to further subdivide the input and output domain of the fuzzy controller according to the change of the error, to improve the system control performance. The simulation results show that the operation scheme proposed in this paper have better system performance than the original scheme of the small reactor system, and controller proposed in this paper have better control performance than traditional PI controller and fuzzy PI controller, what's more, the designed control system also showed better antidisturbance performance in lifting experiment between 100% and 80% working conditions. Finally, the experimental platform formed by connecting the digital small reactor with Matlab/Simulink through OPC(OLE for Process Control) communication technology also verified the feasibility of the proposed scheme
Elsisi, M.,Abdelfattah, H. Korean Nuclear Society 2020 Nuclear Engineering and Technology Vol.52 No.3
Reactor control is a standout amongst the most vital issues in the nuclear power plant. In this paper, the optimal design of variable structure controller (VSC) based on the lightning search algorithm (LSA) is proposed for a nuclear reactor power system. The LSA is a new optimization algorithm. It is used to find the optimal parameters of the VSC instead of the trial and error method or experts of the designer. The proposed algorithm is used for the tuning of the feedback gains and the sliding equation gains of the VSC to prove a good performance. Furthermore, the parameters of the VSC are tuned by the genetic algorithm (GA). Simulation tests are carried out to verify the performance and robustness of the proposed LSA-based VSC compared with GA-based VSC. The results prove the high performance and the superiority of VSC based on LSA compared with VSC based on GA.
Yoon Dong-Hee,Lee Hansang 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.1
Voltage control has gained importance owing to the increase in the installation of renewable power on the distribution level power system. Grid connections for renewable power can cause voltage problems, thus necessitating the employment of a voltage control device or technology to control the voltage profle of the line. Traditionally, a fxed shunt reactor (FSR) is used to control voltage. However, it can only control the on/of state for the case when the capacity is fxed. Recently, a variable shunt reactor (VSR) capable of controlling the size of the inductance for each stage has garnered attention. The voltage change occurring upon switching is lower in case of VSR than with FSR, and graded reactive power compensation is possible. Consequently, VSR can be used to efciently control the voltage. For the actual incorporation of VSR, a power system analysis is necessary. This study developed a VSR analysis model in a form that can be used in a commercial program PSS®E. The developed analysis model included various factors of VSR that are necessary for the power system analysis, and various scenarios were introduced for verifying the validity of the model through appropriate simulations.
냉각수 유속 변화에 따른 고주파 용접기용 가변 리엑터 / 커패시터의 변형에 관한 연구
국정한(Kook, Jeong-Han),박광진(Park, Gwang-Jin),김기선(Kim Key-Sun) 한국산학기술학회 2011 한국산학기술학회논문지 Vol.12 No.10
본 논문에서는 고주파 용접기의 가변 리엑터 및 커패시터를 해석하여 최적화 설계 하였다. 고주파 용접기의 극판 부분은 콘덴서의 역할을 하기 때문에 큰 정전 용량의 콘덴서를 만들기 위해서는 유전율이 큰 재료의 선택과 극 판의 면적을 크게 하고, 극판의 간격을 얇게 하여야 한다. 하지만 많은 전류가 흐르기 때문에 저항이 발생하여 열이 발생하게 된다. 이러한 극판의 열 변형을 막기 위하여 냉각수 등을 이용한 방법으로 극판의 열을 식힌다. 이때 극판 의 변형 및 온도에 따른 냉각수의 속도를 최적화 하였다. In this paper, variable reactor and capacitor for high-frequency welder are analyzed by optimum design. As the polar panel of high-frequency welder has the role of condenser, the material with the high rate of induced electricity has to be selected in order to manufacture the condenser with the great power cut. And the area of polar panel must be large and the gap between panels must be thin. On the contrary, the resistance is generated and the heat is happened because the large current is flown. To prevent the thermal deformation of this polar panel, the temperature can be lowered by using cooling water and so on. At this point, the speed of cooling water due to deformation and temperature of polar panel can be optimized.
0.5 MWth 급 케미컬루핑 연소시스템의 공기반응기 고체 체유량에 미치는 조업변수의 영향
류호정(Ho-Jung Ryu),이도연(Doyeon Lee),남형석(Hyungseok Nam),조성호(Sung-Ho Jo),이승용(Seung-Yong Lee),백점인(Jeom-In Baek) 한국에너지기후변화학회 2018 에너지기후변화학회지 Vol.13 No.2
Effects of gas velocity and solid circulation rate on solid holdup profiles in an air reactor were measured and investigated in a 0.5 MWth chemical looping combustion system. The measured solid circulation rate increased as the gas input velocity through the left side of lower loop seal and the measured solid holdup increased as the solid circulation rate increased. However, solid holdup decreased as the gas velocity in the air reactor increased. The choking was observed at low gas velocity and high solid circulation rate conditions. Therefore, a suitable operating condition should be selected to avoid the choking in the air reactor by adjusting gas velocity in the air reactor and solid circulation rate.
이수원,신성민,정성균,조항진 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.5
In this study, we evaluate the thermal-hydraulic performance and economics of Printed Circuit HeatExchanger (PCHE) according to the channel types and associated shape variables for the design ofrecuperators with Sodium-cooled Fast Reactors (SFRs). To perform the evaluations with variables such asthe Reynolds number, channel types, tube diameter, and shape variables, a code for the heat exchanger isdeveloped and verified through a comparison with experimental results. Based on the code, the volumeand pressure drop are calculated, and an economic assessment is conducted. The zigzag type, which hasbending angle of 80 and a tube diameter of 1.9 mm, is the most economical channel type in a SFR usingCO2 as the working fluid. For a SFR using N2, we recommend the airfoil type with vertical and horizontalnumbers of 1.6 and 1.1, respectively. The airfoil type is superior when the mass flow rate is large becausethe operating cost changes significantly. When the mass flow rate is small, volume is a more importantdesign parameter, therefore, the zigzag type is suitable. In addition, we conduct a sensitivity analysisbased on the production cost of the PCHE to identify changes in optimal channel types