Search

Ryu, G.H.; Kim, H.; Kim, Y.-G.; Chon, K.-H.; Joo, J.Y., and Moon, C.-J., 2021. GIS-based site analysis of an optimal offshore wind farm for minimizing coastal disasters. In: Lee, J.L.; Suh, K.-S.; Lee, B.; Shin, S., and Lee, J. (eds.), Crisis and Integrated Management for Coastal and Marine Safety. Journal of Coastal Research, Special Issue No. 114, pp. 246–250. Coconut Creek (Florida), ISSN 0749–0208. The horizontal force transmitted to the turbine and the substructure of a wind power system is very important factor in system safety, and such a system is particularly vulnerable to large-scale coastal disasters such as earthquakes and typhoons. Wind power systems built offshore and on coasts have reduced economic efficiency due to the increase in initial investment costs, because they require a more robust design when installed in areas vulnerable to coastal disasters. The western and southern seas of Korea have a relatively shallow water depth, which is advantageous for the construction of offshore wind farms. However, since it is close to the Pacific Rim, the probability of an earthquake is relatively high compared to those in other regions, and the frequency of typhoons is higher as well, so a more detailed site analysis is necessary. In this study, the GIS technique was used to select an optimal site for wind farms with a focus on reducing the risk of coastal disasters. The current state of earthquakes in the western and southern seas of Korea as well as the movement path and intensity of typhoons affecting or passing through the western and southern seas were also analyzed in a complex manner. As a result, an optimal site for an offshore wind farm with the lowest risk of coastal disasters was analyzed.

Kim, H.; Moon, C.-J.; Kim, Y.-G.; Chon, K.-H.; Joo, J.Y., and Ryu, G.H., 2021. Analysis of atmospheric stability for the prevention of coastal disasters and the development of efficient coastal renewable energy. In: Lee, J.L.; Suh, K.S.; Lee, B.; Shin, S., and Lee, J. (eds.), Crisis and Integrated Management for Coastal and Marine Safety. Journal of Coastal Research, Special Issue No. 114, pp. 241–245. Coconut Creek (Florida), ISSN 0749–0208. The ground friction force is lower in coastal and marine areas than it is on land, and there is a relatively high frequency of strong winds in such areas, which substantially affects the life and stability of wind turbines. In particular, the strong wind at the bottom of the atmospheric boundary layer is generated by a combination of thermal and mechanical factors, so there is always a risk due to vertical wind shear and strong turbulent gusts. Therefore, to prevent physical loss of wind turbines located in the atmospheric boundary layer, it is necessary to analyze the wind condition through a more accurate atmospheric stability analysis. In this study, observation data from the Boseong Standard Meteorological Tower are examined to select strong wind cases in the lower atmospheric boundary layer, and the vertical distribution characteristics of the wind resources are analyzed according to the Monin-Obukhov length (MOL). The results confirmed that the vertical wind velocity gradient caused by atmospheric stability mainly changes when the atmosphere is in the near-neutral state at night during the winter.

Wind turbines interact with the wind to capture its kinetic energy and convert into useable energy. A wind control system is a complex and critical element in a wind turbine. Wind turbine control system consists of two feedback loops. One is the generator torque control loop, and other is the pitch control loop. In this paper, deals with a method for the generator torque and pitch control in MW class wind turbine of PMSG. Based on the results of the simulation, the rated wind speed for the area before and after the proposed algorithm output of the wind turbine control was to be performed under the control area properly.

The recent trend is that diesel power generation on islands where its prime cost for power generation is high is replaced by new and renewable energy. Therefore, south Jeolla province is progressing the construction project of self-sufficient islands for the areas where power is supplied by depending on diesel generators, which is the project that power is supplied through eco-friendly energy source using sunlight, wind power and energy storage device etc. However, it is difficult to construct new and renewable energy source with the capacity to respond to the load perfectly due to its environmental and geographical conditions regarding capacity design of new and renewable energy. Besides, Microgrid design considering appropriate capacity design of the system components and efficient operation is required through the analysis of climate conditions and load patterns from the design stage for optimal composition of a hybrid system with economic feasibility. Therefore, this study is aimed to conduct a research on optimal combination, capacity calculation and economic feasibility by comprising a hybrid power generation system which will replace 40% of power generation by diesel as new and renewable energy source for Geomun Island where has more than 300 households and requires expansion of the facility among islands located in southwest coast.

The majority of electric power in the domestic manned islands with off-grid power system is supplied by the diesel generators. However, in the case of off-grid islands the fuel cost is more expensive to inland areas and difficult to transport them to islands. So the development of renewable energy system using natural resource have been recently introduced. But renewable energy that depend on the natural environment, it is necessary to organized the hybrid system with existing diesel engine because the energy is difficult to maintain stable electric power. This paper presents the results of a feasibility study of hybrid system with energy storage system such as wind, solar, battery and diesel engine. The study included off-grid island as the Seogeochado islands located in Jeolanamdo Province. And, the paper proposed a optimal capacity of hybrid system configuration to maintain carbon free with minimum investment cost. the analysis of economic adaptability performed by HOMER program.

In this paper, the 50kW aerogenerator which is applicable to the microgrid was designed and analyzed by using commercial simulation program Maxwell 2D. Particularly, the suggested PMSG to reduce the cogging torque introduced the offset and skew concept. The suggested optimal value of offset and skew was decided by 2mm and 60 degree of electric angle. The simulation results of the PMSG when load operation condition showed the average harmonic distortion 1.3%, voltage 322.41V, current 94.95A, and iron loss 9.73W, eddy current loss 73.68W, copper loss 3.52kW. The capacity of aerogenerator calculated 61.56kW, and the suggested design process can be applied to higher capacity generator.

A meteorological(met) tower is the first structure installed during the planning stages of offshore wind farm. The purpose of this paper is to design the met tower with tripod bucket type support structure and to install the sensors. The support structure consist of a central steel shaft connected to three cylindrical steel suction buckets which is more cheaper than monopile or jacket type. And the remote wind condition sensors and marine monitoring equipment, including adcp, pressure type tide gauge, wave height sensors, and scour sensors, remote power supply are installed. The manufactured met tower constructed on sea area which is in front of Gasa island. All of functions of met tower showed normal operation conditions and the wind data got by remote data collection system successfully.

The objective of this paper is to suggest a design topology of permanent magnet synchronous generator with 2,000kW capacities for wind turbine. The suggested topology is to provide 3 split magnet PMSG instead of single magnet, and performed an analysis of eddy current loss and iron loss for suggested type using ansoft maxwell commercial program. The simulation results of suggested magnet type show there duction of eddy current loss as 13.87kW with loadless conditions and23.48kW with rated conditions, but iron loss for rotor yoke show the in creasing trend as2.2kW with loadless conditions and 0.2kW with rated conditions. The suggested 3 split maget type is to identified as more useful for 2,000kW PMSG.

In the case of the Back EMF voltage contains the harmonics, the motor torque ripple and vibration is occurred by the current pulsation, because IPMSM control algorithm is the model which is assumed that it contains a sinusoidal Back EMF voltage. To improve ride quality, in the case of IPMSM for EV, improving the torque control characteristics is necessary. Therefore, there is a need to minimize the influence of the harmonics. In this paper, the investigation to decrease the current distortion factor has been performed for improving torque control characteristics by applying the non-sinusoidal Back EMF to IPMSM model.

The small wind generator with existing mechanical control system has a frequent failure and malfunction, and its maintenance is difficult. In this paper, an electric control method using a boost converter for small wind generator was suggested. The suggested 2-level boost converter control device was manufactured and its experimental operation were conducted on a wind generator with 200 [W] capacity. As a result of experimental device, the control by a boost converter was executed at the point that the output voltage of a wind generator became 36 [V] so it could be identified that the output voltage of a wind generator diminished and then it became 0 [V] after 5 [sec]. Besides, in case of applying the method suggested in this paper to a small wind power generation facility for street lights, it is expected to reduce its maintenance by preventing a frequent failure of a generator and to improve its utilization rate.

New & renewable energy becomes a crucial subject to solve the problems inherent in the current energy resources, which results in the fast development of the new & renewable energy industry worldwide. However, not only its base is still weak but the high initial investment for technology development and certain scale of an energy market are required in many cases. For this reason, many countries in the world, including Korea, run the energy policies to foster the new & renewable energy industry such as RSP and FIT. In general, a policy should be established to take various, intertwined interests as well as a number of variables related to economic, social, environmental, and international matters into comprehensive consideration. For new & renewable energy industry, there are many variables to be considered and indexes necessary for evaluation but it is hard to take all of them into account. Even though they were considered, no criteria are available for use in a consistent manner. Therefore, this study plans to develop an evaluation model for the Korean new & renewable energy policy.

It is evident that in the wind energy business as an economic activity there is a close relationship between the wind speed and the revenues. The wind turbine test facility for wind turbine accreditation is intended to be used by the industry for testing of both main components and systems. This paper suggest the wind test site for certification of prototype wind turbine with international regulations. The test site has an environmental permit for wind turbines with a maximum hub height of 120m and a rotor diameter up to 120m, and can accommodate prototypes with installed electrical powers up to 5MW each. A wind turbine manufacturer can lease the location for a period of type certification. And also researchers are the development of new methods for measuring the influence, performance and durability of the components, a mathematical and numerical modelling of component responses by using the site.

In this paper, a ripple input current embedded switched-inductor Z-source inverter (rESL-ZSI) and a continuous input current embedded switched-inductor Z-source inverter (cESL-ZSI) are proposed by inserting two dc sources into the switched-inductor cells. The proposed inverters provide a high boost voltage inversion ability, a lower voltage stress across the active switching devices, a continuous input current and a reduced voltage stress on the capacitors. In addition, they can suppress the startup inrush current, which otherwise might destroy the devices. This paper presents the operating principles, analysis, and simulation results, and compares them to the conventional switched-inductor Z-source inverter. In order to verify the performance of the proposed converters, a laboratory prototype was constructed with 60 Vdc input to test both configurations.

To install a wind power generator, the survey on the wind environment resources must be conducted in advance. The survey on the wind environment resources is to collect and analyze data regarding the wind speed and direction on a data logger. The data logger consists of a sensor, signal processing circuit and storage device. According to the analysis of the stored data, the amount of power generation by the types of generators can be predicted and the most optimal generator including safety grade can be selected, and in case of installing a generator in the future, it can be utilized as basic data regarding supporting base and foundation construction method of survey points. Data logger was developed for a small wind power generator that is suitable for the international standard(IEC 61400) by using DSP-F28335 micro controller in this paper. It was developed to measure the wind speed of 1 [m/s]~17 [m/s], the wind direction of 0 []~359 [], and temperature of -30 []~50 [], and the comparative experiment with other companies` data loggers was conducted, and an error was measured to be less than [m/s] for wind speed and less than +1 [] for wind direction.

In this brief, a new adaptive neurocontrol algorithm for a single-input-single-output (SISO) strict-feedback nonlinear system is proposed. Most of the previous adaptive neural control algorithms for strict-feedback nonlinear systems were based on the backstepping scheme, which makes the control law and stability analysis very complicated. The main contribution of the proposed method is that it demonstrates that the state-feedback control of the strict-feedback system can be viewed as the output-feedback control problem of the system in the normal form. As a result, the proposed control algorithm is considerably simpler than the previous ones based on backstepping. Depending heavily on the universal approximation property of the neural network (NN), only one NN is employed to approximate the lumped uncertain system nonlinearity. The Lyapunov stability of the NN weights and filtered tracking error is guaranteed in the semiglobal sense.

Recently, many researchers have shown great interest in wind-photovoltaic hybrid generation system which promotes electric power supply safely and progress of energy usage efficiently with complementary cooperation of a wind generation system and photovoltaic generation system. To use this hybrid generation system stably and effectively, we established a system which can acquire, analyse and save data and monitored remotely using internet. We constructed the signal conditioning circuit and used many kinds of converters to measure physical quantities such as wind velocity, intensity of illumination and temperature as well as many kinds of voltage and current for AC and DC. we acquired data from computer with data acquisition board, developed server program and client program which can download data that is monitored and saved in realtime at remote place. We analysed the measured data in relation to many conditions such as time and weather conditions.

This paper proposes a modified converter for use in photovoltaic system. In the modified converter, the voltage ratio of output to input is equal to that of the general boost converter. The difference between the two converters is the configuration of output terminal. Therefore, the working voltage of an output capacitor and the value of its capacitance can be lower than those of the general boost converter. This paper also presents an efficient parallel driving scheme to increase output power and to reduce the output voltage ripple. The parallel driving method using the modified converter and current mode control gives a good solution for alleviating the current sharing unbalance problem. It reduces the output voltage ripple by increasing the equivalent switching frequency of the modified converter. The performance of the proposed converter system is verified through computer-aided simulations and experimental results.

A direct adaptive state-feedback controller for highly nonlinear systems is proposed. This paper considers uncertain or ill-defined nonaffine nonlinear systems and employ a static fuzzy logic system (FLS) with an on-line structuring algorithm. The FLS approximates and adaptively cancels an unknown plant nonlinearity. A control law and adaptive laws for unknown fuzzy parameters and bounding constant are established so that the whole closed-loop system is stable in the sense of Lyapunov. The tracking error is guaranteed to be uniformly asymptotically stable rather than uniformly ultimately bounded with the aid of an additional robustifying control term. No a priori knowledge of an upper bound on an lumped uncertainty is required.

An efficient switching scheme to equalize the size of transformer is proposed for a multilevel inverter employing cascaded transformers, which have a series-connected secondary. All transformers can be designed with the same size regardless of their position because the maximum magnetic flux imposed on each transformer becomes exactly equal each to each. Therefore, identical full-bridge inverter units can be utilized, thus improving modularity and manufacturability. The fundamental idea of the proposed switching pattern is illustrated and then analyzed theoretically. The validity of the proposed switching strategy is verified by experimental results.

This paper describes the design of an output-feedback controller based on an adaptive fuzzy observer for uncertain single-input, single-output nonlinear dynamical systems. We have focused on the realization of a minimal dynamic order for the adaptive fuzzy observer. For this purpose, we adopt an adaptive fuzzy observer in which no strictly positive real (SPR) condition is needed and we combine a self-structuring scheme with an on-line estimation of fuzzy parameters. By using this proposed scheme, we can reduce the dynamic order of the adaptive output-feedback fuzzy control system. The Lyapunov synthesis approach is used to guarantee a global uniform ultimate boundedness property of the state estimation error and tracking error, as well as all other signals in the closed-loop system. No a priori knowledge of an upper limits on the uncertainties including optimal parameters and modeling errors is required. The theoretical results are illustrated through simulation examples.

Wind power and photovoltaic(PV) systems are getting into the spotlight as substitute energy. But problem is happened stability by speed change of wind and the power output of the sun`s ray. The power output amount according to velocity of wind power system. System breakdown can happen at change of sudden velocity, typhoon and night. This paper shows a automatic tail safety brake controller based on feedback control using wind velocity. The operation of automatic tail safety controller verified by manual test. PV system is a energy change system by temperature of sun`s ray and cell. Maximum power point tracking(MPPT) is used in PV systems to maximize the photovoltaic array output power. In existed PV system is low output and changeable DC voltage for boost and filtering the buck-boost converter use. But, this paper established deformed DC-DC converter. Changed Buck-boost converter`s unlined output current to line output current using DC-DC converter. This is effect that reduce ripple of output current. Proved through an output waveform comparison experiment. Finally, tail safety brake controller is established to wind turbine system for stability elevation and DC-DC converter is established on PV system for stability output.

The bolier systems of coal fired power plants are large, non-linear systems with numerous interactions between its component parts. In the analysis of such complex systems, dynamic simulation is recognized as a powerful method of keeping track of the myriad of interactions. The boiler system consists of air/gas system and water/steam system. Due to recent reinforcement of environmental regulation on pollutant discharge and requirements of design validation on properites of boiler, the commercial programs are used for the analysis of boiler system. This paper addressed to the development of model using MMS(Modular Modeling System) developed by EPRI(Electric Power Research Institute) as the simulation tool. The developed model using MMS is tested for the design and local data on boiler combustion system of korea standard coal fired power plant boiler. The simulation results show that the developed model well reproduces responses of the combustion system with less than 5% error under steady state and transient state conditions. The developed model for analysis of the combustion system in this paper is general and applicable to any type of coal fired power plant.

Given the massive early investment needed for the construction of large offshore wind farms, the ROI (return of investment), which can guarantee sufficient profitability, should be secured in advance. The highest priority in terms of determining profitability is to estimate the power production volume of an offshore wind farm based on surveyed wind resources. The maritime measurement of wind resources in Korea has only been performed at one point in the water off the coast of Wido. And the measurements released by the Korea Meteorological Administration were used, as there are no available long-term measurements for other areas.

Korea has been developing coast has been developing wind energy on land for a long time, and the government is in preparations of an offshore wind farm for the first time. The conditions of the wind rose affect not only the structures of wind turbine, but are also important in predicting the future energy production rate. If an offshore wind farm is to be composed, it is the most important factor to predict the amount of energy produced each year on the predicted site of the wind farm. In order to predict this, a Met mast must be installed at the selected site for more than one year to analyze the measured wind rose resource. This study has analyzed the wind rose resource by using the data obtained through the Met mast of 60[m] height installed on an island of the Southwest coast, and the measured data has been applied on WindPRO and WAsP programs to predict the annual energy production based on the calculation of the energy production under the assumption that a 100[MW] level offshore wind farm is composed at the selected site. The result was 313,672.24[MWh/year] if 50 2[MW] level wind generators are applied, thus a usage rate of 35.81% is expected.

The photovoltaic module shows difference in efficiency according to the manufacturing method, and in case of operation mode, identical PV modules with the same manufacturer also become to show difference data in generation efficiency according to their management method. In other words, the unbalance of efficiency in specified modules connected as a series or a parallel array reduces the total generation efficiency, so there is a required for studies based on the electrical properties of modules exposed to an outdoor environment. This paper suggest the real time measurement system for the individual state of a fixed PV array and get the experimental data from its devices. As a result of analyzing the experimental data, we are find 4 PV modules with serious deterioration. The initial parameters of PV modules are estimated by using computer simulation and used the basis of PV module deterioration.

There are lots of simulation methods can be used in electronic circuit analysis such as Psim, Matlab and Pspice etc. Here the analyses about 3-Phase Z-Source inverter are done to find the characteristics when different control method is applied. There are lots of control methods can be used in the 3- phase Z-Source inverter. In this paper several typical control methods are analyzed and compared through the simulation in the PSIM and Matlab.

In this paper, we proposed an electric circuit using one common arm of H-Bridge Inverters to reduce the number of switching component in multi-level inverter combined with H-Bridge Inverters and transformers. And furthermore we suggested the new multi-level PWM inverter using PWM level to reduce THD (Total Harmonic Distortion). We used the switching method that can get the same rate of usage at each transformer. We tested the proposed prototype 9-level inverter to clarify the proposed electric circuit and reasonableness of control signal for the proposed multi-level PWM inverter.

An adaptive neural control problem of SISO fully nonaffine pure-feedback nonlinear system is considered in this paper. The main contribution of the proposed method is that it is shown that the control problem of the pure-feedback system can be viewed as that of the system in the standard normal form. As a result, proposed neural control algorithm is much simpler compared to the recently proposed backstepping-based neural controllers. Depending heavily on the universal approximation property of the neural network (NN), only one NN is employed to approximate lumped uncertain nonlinearity in the controlled system. It is shown that the Lyapunov stabilities of the NN weights and filtered tracking error are guaranteed in the semi-global sense.

A new adaptive fuzzy controller for uncertain strict-feedback nonlinear systems is proposed. All the previous approximator-based adaptive control algorithms for the strict-feedback nonlinear systems are based on backstepping scheme and guarantee semi-global closed-loop system stability. This paper proposes a new globally stabilizing adaptive fuzzy controller for strict-feedback nonlinear system without backstepping. To this end, an online self-structuring adaptive fuzzy system is employed. The proposed adaptive fuzzy controller is considerably simpler than the previous ones based on backstepping. Only one FLS is employed to approximate a lumped uncertain nonlinearity, which highlights the simplicity of our proposed control scheme.

In this paper, we proposed the electric circuit using one common arm of H-Bridge inverters to reduce the number of switching components in multi-level PWM inverter combined with H-Bridge inverters and transformers. And we proposed a switching method that can get same rate of usage at each transformer. We tested the proposed prototype inverter to clarify the proposed electric circuit and reasonableness of the control signal.

A new multilevel PWM inverter is presented to improve the system characteristic of a prior 11-level shaped PWM inverter scheme. In appearance, it consists of three full-bridge modules and three cascaded transformers; therefore, the configuration of the proposed multilevel PWM inverter is equal to that of the prior one. Only the turn-ratio of a transformer and its corresponding switching function are different from each other. Based on these differences, the proposed multilevel PWM inverter has two promising advantages. First, output voltage levels increase almost two fold. Consequently, it can generate more sinusoidal output voltage waves. Second, due to a suitable switching pattern, it lightens power imposed on the transformer, which is used for compensating output voltages with chopped pulses between steps. Operational principle of the proposed 19-level shaped PWM inverter is analysed with comparisons of the prior 11-level shaped PWM inverter. The validity of the proposed inverter system is verified by computer-aided simulations and experimental results based on a 1kW prototype.

In this paper, a cancellation method of background field using a magnetic compass sensor is proposed for a magnetometer based autonomous vehicle. The magnetic fields from sample magnets are first measured to determine the characteristics of the field patterns as the basis for detection and position identification. The properties of the earth's magnetic field on the recognition of magnet field patterns are discussed. Also presented in the paper is a discussion of a position sensing system with a cancellation of the earth's field. The position sensing technique was implemented in the guidance of autonomous vehicle. By the experiment, it is verified that the proposed cancellation method of background field can be useful for an autonomous vehicle.

Many conventional thermal power plants were started up and shut down infrequently and the operating loads were constant at the normal operation. In contrast, in recent years, with the participation of nuclear power generation and from the varied pattern of load consumption, it has been required that the plants should be operated efficiently. Thus, the DSS (daily startup shutdown) and WSS (weekly startup shutdown) have been carried out, and the plant startup, shutdown and load variations have become very frequent. This tendency is reflected also on water conditioning systems. The Poryoung thermal power plant designed with the concept of DSS operation, and also, the CIS (chemical injection system) as one of water conditioning systems have automatic operation mode to maintain constant water quality with conventional control system. Unfortunately, the control system does not maintain the set point of water quality. The engineer revise the control concept with F(x) function, but the results of test operation do not show satisfactory performance. This paper discussed the parameter identification of CIS using neural network model and suggested a fuzzy control system for CIS to improve the control performance and showed the validation of suggested system using simulation.

This paper describes a control scheme for on autonomous vehicle with visual sensors, which uses visual information to guide itself along roadways. The control system integrates visual data into the servo process directly, instead of subdividing the process by reconstructing three-dimensional shape from two-dimensional image data, and relying on geometric reasoning for a vehicle-centered representation of the road. An artificial neural network system is used for determining the steering angle required to move the vanishing point and vanishing line of the road to the desired position in the camera image. The validity and the effectiveness of the proposed control scheme are verified by a computer simulation of the autonomous vehicle's performance.

The Sea Water Lift Pump (SLP) system is responsible for maintaining the open canal level to provide the suction flow of Circulating Water Pump (CWP) at the set point. The response of the SLP system is so slow that it is difficult to maintain an optimal open canal level by manual or two step pump speed control operation and to reduce overflow of seawater. The objective of this paper is to apply the fuzzy control method, which can utilize the flexibility and the heuristic operation strategy employed by operators, to SLP system in fossil fired power plant. In order to verify a proposed fuzzy system, we developed simplified models such as mathematical model of SLP, CWP, seawater level and intake canal. The result of the simulation test shows that the proposed fuzzy control method can reflect successfully the experience gained in skilled manual operation. It is expected that the fuzzy control can contribute to the reduction of power consumption of SLP, human error and man power, and to the improvment of the reliability and safety of the plant operation.